Good grief.
If my DP wanted children with me and someone close to him became pregnant, he would be glad for them while obviously wishing things were that way for him, but he would accept that it's just the way things were at that moment.
He wouldn't dream of saying that this was my destiny, not his, as that would be downright spiteful. Even if he couldn't help feeling strongly that way, he would rather leave to try with someone else than use it to hurt me, because I am his friend as well as his partner.
Despite being a self-confessed keep fit freak himself, there is no way he would discuss what can be done about my weight with his side of the family and even if they felt that they had something to do with it, he would take my side over theirs.
If I had abnormal cells, he would be worried about my health first and foremost, not angry about having to put IVF aside. If I did not want him at a health appointment, he would respect that, but if I was being admitted for brain scans, you bet your ass he'd be in his car in the way there before you could say "MRI"!
What I'm trying to say is that I'm not just writing all this to rub it in about how "lucky" I am, because luck had nothing to do with it - this is the bog standard anyone should expect from their partner.
I know I haven't gone through even the prospect of IVF but I really do think this needs to be put on the back burner while you both focus on the relationship. If he, however, doesn't want to budge, then please don't think he is your last chance. You sound very lovely, brave and determined and I am sure that you would be able to find much nicer and more supportive to go through this with you.