@ilovetakeaways
I know some people may think you are being unreasonable, or OTT, but I have to say that this would hurt me too. I understand you must feel very left out.
That said, as a few posters have said; your partner hasn't done anything wrong really - although it would have been nice if he had said 'do you mind if I go to my son's party? But I'm really sorry it's just me who is invited.' I mean he doesn't HAVE to do that, but it would have been nice to have done it, to make you feel more secure.
Also, his ex hasn't done anything wrong either. If I was her, I would not invite my ex's new partner either; especially as we had never met/had nothing to do with each other. Like a few other posters, I am concerned that you have been with this man 3.5 years, and you have still never ever met his ex/the mother of his son. Why is that? Have you never been there when he goes to see his son/pick him up/has access to him?
@Shelby2010
So, by your last post it’s not the party, more that DP is stringing you along with talk of marriage & babies. He’s saying what he thinks you want to hear without showing any interest in moving the relationship forward?
I am also concerned that he doesn't seem to be in any rush to take the relationship to the next level. Do you think he mentions marriage one day, to keep you dangling OP?
Sorry you are feeling like this OP. But you do know this kind of thing will keep happening right? Can you deal with this? Is it possible to make a connection with his ex? I mean, reach out and try to offer a hand of friendship? I would understand if not, but it's just a idea.
I know several posters have said they have been with a man before who had kids with an ex, and they never met the ex after 4 or 5 years, but I think that the exception rather than the rule tbh.
Good luck. I wish you well. 