ok, thanks. Look, I do not take the fundamentalist stance of, for example, Madamez. I wouldn't go as far as to say he is dangerous as there are clearly lots of things which work for you both too. But I know so many men who moved in to their wives' homes, for any number of practical reasons, and for whom it is really no issue at all. I really think you need to ask him to draw a line in the sand on this issue, it is a fruitless use of nervous and emotional energy for you both. In reading what you write about him, he comes across as first and foremost very insecure, in himself and in regards to the role he has in the household. You can try to reassure him on this so that he understands that he is valued and that you are so happy to be with him instead of with your ex. And if that really does not stop these issues then, yes, as has been said, they probably go deeper than you or he realise and he needs to find a resource(s) to understand what is going on for him.
If I were you (which, as a man, I am clearly not!), I would steer a very clearly communicated path:
I was with someone before you.
I left him, I didn't want to be with him.
I met you, I want to be with you.
You are a better partner in every way than my ex.
Of course I cannot change anything about my past or my situation when I met you - and neither would I want to.
You have to accept how I got here and I have to accept the same about you.
Your jealousy is irrational and no matter how much you bring it up, there is absolutely nothing I can do about it. It would be different if you were jealous of someone I see in the present, at work for example. But you can say all you want about this house and my ex, there is nothing I can do to change my choices of the past.
If you continue to have such a big issue with the house, we need to look at practical ways of moving. If we cannot find a way, we will stay here as it is to the advantage of all concerned. If we do not move, it is no reflection on you as a partner, a man, or a dad.
While I sympathise with the fact that you are suffering inside because of this, I cannot continue to support you in your distress. As I have stated earlier, there is nothing I can do to change what came before. We can shape our future together, we canot change our pasts.
If these issues continue, in spite of my reassurances, I think you may need to look at what might be lying below the surface to generate these feelings of jealousy and possessiveness. You have so many qualities and I love being with you but possessiveness is deeply unattractive and if you cannot find a way with me to overcome it, you will have to find resources elsewhere, for example talking it through with a counsellor. We can go and see one together if you wish.
Because I we cannot find a way to move through this, and you do not show the desire to find a way for yourself, I think we will reach an impasse which may be 100 times harder to move through than the one we are currently in.
I hope that helps