How to come to terms with it

Me and my husband wanted 2 children. Now that we have had one who has been very difficult through the past year (aren't they all? But seriously a lot of 'issues' over this year) he says he is NEVER having another child. I respect this choice but I'm obviously heartbroken as I wanted another someday. I'm just so upset my son won't have a sibling and I won't experience this ever again. How do I deal with it?