Sex question TTC#1 (maybe tmi)

Alison
I have a very loving husband who wants to get me to climax before withdrawing. Does he need to withdraw right after ejaculation in order for his swimmers to survive? Or can he stay in a little longer? I don't want him to kill them all so I can climax. Also I've heard mixed thoughts on whether a woman needs to climax in order to get pregnant. Thoughts? Thanks!