My boyfriend doesnt think we will last?

Lately, me and my boyfriend have been getting into arguments. Im pregnant so my hormones are out of wack which usually ends up turning out into a fight and I feel like I start it. He says he understands that I am moody but I can tell he is starting to get annoyed with it. We are giving our baby up for adoption (open) and planning on going up there over Christmas because the adoptive parents invited us. We were talking about it tonight and somehow our relationship got questioned after the baby is born got brought up. And he said how "we never know what's going to happen after" and "if we aren't together, we can still go see the baby" I know he was being truthful but I didn't like what I was hearing. He didn't seem to be very confident in our relationship after and that saddens me. What should I say to him to make him maybe feel more confident about our relationship and future?