Oh dear I am going to get flamed here.
But first of all @forrestgreen will you please stop telling the OP things like:
'block her ex's number on her parents phone' and 'to tell her parents to stop talking to her ex or inviting him to family gatherings, etc'.
Unless the OP's parents both have severe dementia, the OP has no right to even touch their phones, never mind open them, or to then go into settings and block their phones from receiving communications from her ex.
If you treat anyone else like that other than your own under 16 year old Children ( and even then, if they are about 8 years old or over, you should discuss any issues with th first), then you are being totally controlling and right out of order. Imo you are advocating behaviour that is even more unsuitable than the OP's ex.
Right, if I have had anyone agree with me so far, I know that I am most likely to lose any support in the next minute or two!
@ItsnotaHenryMoore / @Reallycomplicatedpants
and anyone else who is still reading this:
My DexH (and yes I deliberately call him Dear, because until he left me for another woman I had been in love with him, and he was who I believed at the time to be, my best friend, for over a decade. Even more importantly than that, he was, and still is, the DF of my DC), was my first real, and at the time, all consuming love, who I got together with and married, while I was still a teenager.
As well as being completely in love with my DexH, I took my Wedding Vows very seriously, and unless he had somehow turned into an abusive monster, or been a terrible father, I believe that I would have never left him. His timing and method of leaving me was quite frankly shit, but even though it was over 30 years ago, I still care about him as the man I once - at least thought - was my soul mate, and life long partner. I had been his first girlfriend, and he was the first person that I had made love with had penetrative sex with.
In fact when he told me that he was leaving me, and for a work colleague, I found it very hard to comprehend - we had several DC by then, one of whom was still a very young baby - I actually wondered for a while if he had been taken by aliens and had either been replaced by one of them, or had had his brain so badly scrambled by them, that his character was changed both dramatically and drastically.
So (and I am girding my loins here), I do have some, maybe even a little more than some, sympathy with the OP's exH. I was obviously devastated - and hormonal as I had very recently given birth - when my Dex told me that he was going to leave me, and when he did actually go. Many of you will be disgusted with me that I didn't kick him out immediately, but I was still very much in love with him, and I had some sympathy with the fact that he had never had a girlfriend before me. So I thought it was understandable that he had been curious, but I had just never thought that his moral character, and the deep love that I thought we shared for each other, would lead to him doing anything other than wonder what it would be like to 'be' with someone else.
In my turmoil, at the start of my new single status, I turned quite strongly to the religion I had been both baptised and confirmed in - C.o.I. (NI) Christianity - and although I had become a "High days and Holidays" Church goer, I did, as I stated before, take my Wedding Vows very seriously. Unfortunately the first Church I entered (one I had never been in before, and it wasn't during a Service) had some leaflets near the door, one talking about marriage break ups, so I took it, but didn't read it until I got home. When I read it - and even though it wasn't a Roman Catholic Church - it stipulated very strongly that one should not break one's own Wedding Vows, even if your spouse had, even if they had left you (where is Henry V111 when you need him)!
As at that time I felt exactly the same way anyway, I readily absorbed and believed what the leaflet said. Nothing else changed in my infrequency of Church attendance, or my infrequency in reading the bible - I didn't during that stage of my life, or since as it happens, as my beliefs have changed quite a lot; the biggest change being that I still believe very much in Jesus, but I am also convinced that God is not Omnipotent, hence why terrible things can, and do still happen to completely innocent people.
I think that I have digressed too far, which is one of my worst traits these days - nicely mixed in with my verbal diarrhoea! So I will return very soon now to the OP's current situation, I just wanted to add that some weeks later, after picking up that - in retrospect - potentially very damaging Church leaflet, I read a book called
"The Road Less Travelled",
and that book resonated with me very strongly at the time.
It wasn't/isn't an alternative Gospel, but at the time I think I very much agreed with everything it said, however, I haven't read it for many years now, and my memory is nudging me to say that looking back now to the feelings I had straight after reading they were mainly very positive - for me - but I do think that there might have been a section that advised (but I might be totally misremembering this, or erroneously recalling it, so do please take that into consideration) that if we really love a partner, we shouldn't expect them to be (at least) sexually faithful to us, or put another way, we should let them be free to love others in a way that suits them.
Whether I am misremembering that now, or I didn't interpret it correctly at the time, I very much took it to heart. Therefore, when I eventually met my present DH (after some fun times experiencing dating other people, which I had missed out on in my youth - except for some kissing and fumbling with equally young boyfriends), and I realised that I was in love with him, I insisted that I thought we should have an open marriage.
That was not for my benefit, as I knew that I only ever wanted monogamy in my marriage on my side, as I just couldn't envisage, and had no desire to, have sex with anyone else. Maybe that was at least partially because my DH and I were very well matched in all areas sexually. Probably luckily, my DH didn't want, or feel the need to be sexually active with anyone else either, again maybe partly because by that time he was already far more sexually (and relationship wise) experienced than me?
If I had not had my DC to care for, and if I had not had an enormous amount of help, love and support from some amazing family members and friends (and to be fair my new GP as well - we had only recently moved into that area), and maybe if I had not read the book "TRLT", I might have turned into the OP's first exH. So I do have empathy with him, I did very much feel that my DexH's family were also my family, especially after my Dex and I had DC, as these wonderful little beings who had come out of my body, also got half of their genes from my Dex and his family. So to me that meant (and means) that his family were still my family too. Until her sad death, my Dex MiL still sent me Christmas cards signed with love from mum, and I sent her them addressed to mum, but she did it first (!). My DexH's Dad died quite soon after our split, but his mum just a few years ago. I asked if I could attend his DF's funeral, but they asked me not to, but they said they would put my name on the flowers they bought for him, and of course I respected their wishes.
However the OP's exH has never (allowed himself to?) got over his DW leaving him, and then subsequently divorcing him, and if he felt/still feels anything like I did initially about my Dex, then I can easily understand how and why he feels like he does, why he still considers himself to be part of the family, and why he still wants to be part of their lives. The OP has moved on, but in her ex's eyes - and heart - I think he still considers himself to be married to her, and that just because a Judge has signed a couple of forms (and maybe he signed them too), that is no-where near the same thing as going through your Marriage Vows with someone who you consider to be your other half, who when he took his Vows he expected to live with, love, and be loved by, for the rest of his life. Add DC to the mix and in the vast majority of cases (I hope) the seperated couple will still be intertwined for the rest of their lives.
@ItsnotaHenryMoore / @Reallycomplicatedpants
I am sorry, but I really can't understand why you get so upset/annoyed by your exH and father of your two oldest DC, being at family gatherings, Weddings and Funerals? You left him, so presumably you are not harbouring any feelings of love or jealousy for him, and I don't think he was abusive to you or your DC? I feel very sorry for him, as he is presumably turning into an old and very sad and lonely man. I don't think he is trying to control you, nor does his behaviour come anywhere near that of a stalker, as some other pp's have suggested.
I wish he had been able to get over you all those years ago OP, and I am very sorry that he has wasted so much time pining over the family time he shared with you. Unfortunately, unless your DD's (as they are very established adults now who should not be influenced by you over their feelings for their DF) can somehow help their DF get some mental health support, or at least some MH advice, otherwise he may continue to be a nuisance to you, and never really have any true happiness in the rest of his life.
By the way, I am not trying to say that you shouldn't have left him OP, if you had continued to live a presumably unhappy life with him, it would not have made his life any better, and it would almost certainly have had different, and probably worse, negative affects on your DC, and you hopefully deserve to be happy too. If you could somehow try and change your feelings towards him to ones of compassion - without of course giving him hope that you are feeling more warmly towards him, as that would almost certainly prove even more devastating to him once he realised that that isn't the case - you could help yourself by not getting so stressed during those joint family occassions, your DC would not have to feel guilty about whose "side" they were on, on any given occassion, and your DParents could continue to be kind to someone that they probably do have sympathy for.