Maybe one more??

Hi everyone! A little back story: I am 26, divorced from my ex-husband of 10 years, and with a new partner who is 33 for over a year now. My ex and I had 3 children together ages 7, 5, and 2. My new partner has one child who is 5, so together we have 4. I do shared parenting and only have mine 50/50. My partner is fighting for custody currently as he only has visitation with his. We have talked about getting married again one day possibly and having ONE child together one day possibly. We haven’t said it’s never going to happen, but we haven’t agreed that it will either. Kind of just taking it one day at a time. Well yesterday he comes home telling me he thinks he wants to get a vasectomy. I was crushed internally if I’m being honest. We had a miscarriage last spring and ever since then I just don’t feel done. I would love to be able to have a viable pregnancy with him one day, but I feel like he’s dead set on not and didn’t express that well enough to me and I’m just sad. I’m not saying right now I want a baby, but I’m only 26. I’m restarting my entire life with my kiddos right now, who knows where I’ll be or what I’ll want 2-5 years from now. My OB says I have MANY years of incredible fertility left, but I also don’t want to seem selfish in wanting a child with him when I’ve already had 3 and he has 1. We both have incredible jobs, our own home, cars, etc. We are fairly well off for people our ages so finances are nothing to worry about. Idk what to do or say or how to talk to him about how I feel about the vasectomy without seeming selfish. I want him to know I understand, care, and respect his feelings, but what happens if we decide we want another and it’s too late? I don’t want to ever resent him for not letting me have a say too ya know? I went on BC FOR HIM after our miscarriage even tho I really didn’t want too because I have horrible side effects that cause issues with my health, but I did it for him because we both took the loss so hard. Any advice would be so appreciated. I’m trying sooo hard to understand both sides of this. Thank you.