Jessie,
Like Petunia says - just focus on day at a time. You definitely can't make a decision without taking in the factor of a possible relapse. We all know that's the truth of the lives we live with an A. There are no guarantees they won't relapse down the road no matter how "into it" and "committed" they are right now.
You really need to just focus on yourself and make a decision about whether you can deal with a relapse. The best decision for now may be to not make any promises to him, and let him know you have to take it one day at a time. Then if it does occur - you can make a decision then based on the circumstances and how you feel at that point.
Just as he can't promise you he will NEVER drink again, you can't promise him that you will always be there. Have you guys participated in marriage counseling? My AH and I are starting tonight. He's admitted he needs to quit for good and that he needs help...I think we have a good foundation for marriage counseling. I'll let you guys know how it went.
Take care and don't worry so much about the future as it is always uncertain.
Hugs,
Kitkat