Hcross, I've been there. Initially, he was keen to have a child too, but things happened, and one day, he confessed that he wasn't sure any longer, and then that he had changed his mind, for reasons that although I didn't share, I could understand.
I didn't make myself 'get over it', it happened naturally over time. I went from not being able to look at a baby as the longing was tearing my heart out, to genuinely looking at a baby and feeling a massive relief that it wasn't mine. It did take some time time though.
The two factors that helped the transition is firstly that I suddenly became much more tired. The demand of my work increased significantly, and I found that although my kids were becoming more independent, looking after them became more emotionally demanding. I would wake up at night or early morning and imagined having to get up to look after a crying baby rather than turning to the other side and getting back to sleep and that certainly put me off!
The other factor is that with my children becoming more independent, I also rediscovered the joy of my own independence. To ease the emotional pain, I decided I needed to focus my boiling inner energy into something else, so I took up competitive sport. It really worked as I found the more I progressed, the more hooked I was. I also used my disposable income on very nice holidays, that would have been half as much fun with a baby to look after, which in any case, we wouldn't have been able to afford if we'd had a baby as the money would have gone on childcare, or reducing my working hours.
It became a case of 'if I had a baby, I wouldn't be able to take part of these activities' which had become a big part of my life and happiness.
During that time, I also open my eyes to the fact that even though I knew my DH would have loved any 'accident', he really would have found it hard to take on the responsibility of being a parent, and that would have probably led to stress and resentment in our relationship, a likely unspoken 'you were the one who wanted the baby'.
I am now sooooooo relieved that it never happened, I really am. I can't imagine myself with a 5yo, the idea of it makes me shiver! When I see mums my age with young kids, my first thought is to feel sorry for them, even though I know they must be very happy.
I say all this because you seem to have already decided that leaving him is not something you are considering, so it's very much about accepting not having another child.