Why did he change?

[Allitraitors]

I've NCed for this.
Background: I'm 40 & was seriously seeing this bloke for near 2 years and would have loved to have progressed to moving in/engagement but it didn't as he was emotionally aloof, cold, and didn't prioritise us.
I was incredibly upset when it ended, as I was blindsided (although looking back can see there were signals he was less invested than me although was very keen at beginning) and he never explained why. In the weeks leading up he had spoken about a future together.
He was covertly controlling - perhaps not in a 'mean' way - but in what we did (e.g. where we went/who we saw/what we did). I suppose I slotted into his life.
Eventually he behaved very cruelly.
He met someone weeks later (I don't believe there was an overlap) and I was very hurt. Now - a year later - she's moved in and he is like a different person. I should clarify this is not a 'social media showoff' but something genuine, I believe. I don't want him back, but I'm irrationally hurt that he's changed for her (I'm not angry with her of course). I don't know what I'm asking really; an explaination?

Perhaps she brings out the best in him? I can honestly say that my partner of 6+ years has effected many positive changes in me. I'm happier, more thoughtful, more tactful, I think things through for longer (was very impulsive before and still am, but not as much). He puts a different slant on the way I used to see some things.

I guess what I'm trying to say in my clumsy way is that I met my match; we gel incredibly well and he inspires me to be the best version of myself. Maybe that's what the new woman does for him and he's becoming a better version of himself as a result.

Yes, perhaps @BigTubOfLard and I appreciate what you are saying. I think there's partnerships where this certainly happens - I've had it and I think it's a hallmark of a healthy partnership. Only he never seemed emotionally engaged enough to activatly seem capable of this, hence why I'm stumped. Maybe that is it. I wanted more from him emotionally and she's OK with him not giving it. I guess I'll never know! It's moot and it shouldn't sting but it does.

How do you know how he behaves with the new partner? Do you socialise with them, or have mutual friends?

he was emotionally aloof, cold, and didn't prioritise us
He was covertly controlling

Do you think mutual friends, or anyone seeing your relationship with him from the outside, would have guessed he was this way? Did he act coldly towards you, at the beginning of your relationship, in front of other people?

My point (obviously!) is that it's very hard to tell what's happening behind closed doors unless you are inside that relationship. Even if you have a very close source.

He didn't change. You have said you dismissed red flags, and you knew he wasn't as invested as you were.

Hi @EvenMoreFuriousVexation no they wouldn't have realised - only one person mentioned it and they were very close to him. On the contrary, his friends were surprised when it ended. I suppose it's more that he's made significant 'life' steps with her @Aquamarine1029 - which he didn't with me and I really liked him as while he was somewhat aloof (and certainly emotionally cold), he did have good points. And no very close source, just people we know.

Sometimes things just click.My behaviour is totally different to my new gf as it was with my wife. From watching stuff on TV, doing things at weekends. Yes, a lot is still the same but I am acting differently, she has bought that out of me

Sometimes people learn from mistakes they have made in previous relationships .Perhaps he did learn a lesson from his split with you. As for yourself don't spend as long in a relationship you know is going nowhere in future.

Perhaps she makes life easier for him, gives in to his controlling ways or perhaps is a better match or he's not too fussy and rather be in a relationship than be single, but he wasn't for you, don't torment yourself, he really wasn't right for you, when you do move on with someone else, you will barely give him a thought to what he's up to. Wherever you're finding the info out from, tell friends not to tell you, don't look at his social media etc, you need to fade him from your mind.

Maybe he learned something from his relationship with you? Annoyingly he’s now putting it to use with someone else. He saw that his behaviour with you was wrong and cruel and has made a decision to be different? Perhaps friends told him to take a long hard look at himself and it worked? Either way don’t let drag you down. It’s not your problem any more. Hope you find someone who is more emotionally mature next time round.

Why are you torturing yourself with this? I don’t know what you want to hear, “it’s because you were a difficult and unlovable partner and she isn’t”? Or “He’ll never change, he’s the devil, you dodged a bullet”? All those usual tropes.
He has found someone he clicks with and it is that simple. Or at least in appearance. It’s no reflection on you, or even him, just a testament to the fact you weren’t right for each other. There is nothing to be gained from dwelling on this. Sometimes there are no logical answers, attraction and compatibility are not an exact science. Best you move on and find someone better suited to you who connects with you emotionally in the way you need. Nothing can be gained from playing this over and over in your head.

I don't know what I'm asking really; an explaination?

You are asking for someone to understand your pain and others do.

Many have suffered dissapointments, un requited love and heartbreak, sometimes the reasons do not make sense as a pp poster stated there are no rules to love.

Try to distract yourself from ruminating over them, you may end up missing something that should not pass you by.

All these are valid points. Thank you.

And yes, I'm asking 'what was wrong with me?' as it feels like a rejection and it follows a breakup where I had no answers. I think @BeckiWithAnI has it spot on

He hasn’t changed OP. Just all looks good from the outside. That’s my take anyway!