For context, we just started dating about a month ago. His ex (f, idk age) and him were together for 3 years and broke up in January. From what he's shared so far it wasn't a healthy relationship, he got cheated on and is traumatized from some things. I also notice it in his behavior sometimes, like he expects me to get mad or upset for tiny trivial things.
Before we got serious, right when we were getting honest about our feelings to each other, he asked me if I minded that he talks about his ex/exes sometimes. I told him I don't mind, as long as it's relevant and in context. I meant things that might have happened that affected him.
However, he keeps mentioning things I don't have to know and don't want to know. For example, he randomly dropped info about a kink he had and has done before with his ex and it really bothered me as he has physical proof of it. So everytime I see it, my head visualizes it.
The day afterwards I simply told him I didn't need to know that and that wasn't what I meant when I said it had to be in context. I think the same day or the day after, while I was giving him a hug – I mentioned something about me being bigger than him when I wear my boots. He then said he's used to his exes being way shorter and therefore used to bucking down for a hug and that her back hurt during hugs because of it. He didn't mean anything bad with it, in fact he said he appreciates we can be face to face when hugging. I had already mentioned to him that my head instantly visualizes things like that, so I got quiet and distant and we had our first tensed moment that night. Not a fight, just us being a bit distant. I was hurt and he felt bad for bringing the stuff up. He explained he didn't want to and doesn't want to bring her up. Says he's completely over her and honestly has no feelings about her anymore so he doesn't understand why things like this slip out. He said he'll do his best to keep things like that to himself. This was a few days ago.
There were minor things here and there but yesterday was a bit much.
We drove by a lingerie store and he said he's been there before. Sure whatever, i got a bit annoyed but let it go. A few hours later while celebrating my bday with friends, we were talking about sneaking off for 1-on-1 time and thinking of an excuse, when he said he's used the excuse of counting pasta before. Mood ruined, didn't sneak off. A few hours later, driving home, there was a car with a personalized numberplate which said "LastName" of said ex and he said he knows someone with that name. I'm not oblivious so I called it out and asked him "isn't that literally your exes last name?"
He said it has nothing to do with emotions and it's as if he'd mention a mutual friend's name to which I told him that it does have something to do with emotions, since he's not being considerate of mine. He agreed and apologized again and repeated he's trying his best.
I ended up dropping him off instead of staying over like planned and he panicked a bit since he thought I'd be ending things. He told me he really wants things between us to work and is willing to do anything (I wasn't planning on ending things, just needed my space. I was HURT).
I asked him if he'd consider therapy and he finally admitted he might need it and is considering it.
My main question is, how do I deal with this? I've been patient and understanding for a while now and it's starting to get harder. I'm already building up resentment because of those things, but I do want to stay with him and genuinely wish for a future with him. We fit so well and have so much passion for each other and he's already treated me so much better in this one month, than my exes did in a few years.
Is therapy the right thing to consider or does he just need time and how can I support him while protecting my feelings about this?
I've never been in such a long relationship as he has, so I can't truly understand his side but I have been on his side when it comes to having reminders and feeling guilty and shit about them. I didn't mention them to my partners as often as he does tho. Im scared he might not truly be over her. Help