My husband and I married, and he had a child from a previous marriage, 7 years old at the time that I found out I was prego. He didn't really ever act gungho about having more kids, and I was on b/c for 10 years and became pregnant. God makes no mistakes, this baby has a purpose, just trust that, and just know that theres NO way that you husband can look at that baby once he/she is born and deny the love he will instantly feel!
Edit - forgot to add that my husband absolutely supported our pregnancy emotionally, and was very excited when our new son arrived! Life wouldn't be the same with out our latest addition!
Good luck!! Don't stress about it, usually the things we over analyze aren't so bad once we face them.