I went to see what answers you got but they were not included. Perhaps now they remove them after you have answered "So What Happened." I do hope that you had people that avoided any bible aspect and just mentioned practical things to think about.
If you can't ever imagine having a second child, I would recommend that you get your tubes tied. Why you? If you divorce your husband, the woman usually gets to keep the child. Now, he has no child and can't with a new wife. If you (or you and your child) die in a wreck or something, he can't give another woman a child.
If your child should die, you could never have another child. If your child turns away from you for some strange reason, you can't have another child. I have two. I am so glad I had a girl because boys really do LEAVE the nest when they move away to college or get married. No matter how close you were, chances are, he'll see his in-laws more than you because many boys just don't get that attached AND they aren't as involved in your nurturing care when you and your husband are old.
Regarding your comment about loving another child, I didn't believe for years that I could love my new girl as much as my 10 year old boy. Well, I do, absolutely. And we're closer since he turned 15.
So, unless your husband could never anticipate wanting another child no matter what, okay, let him get fixed.
As far as your getting fixed, I'd put that off awhile unless you can say to your self that even if you lost your child, you wouldn't want to be a mother again, ever, because you don't really enjoy mothering enough.
Best wishes.