You sound like you recognize all the problems he has, and describe yourself as co-dependant. That is a recipe for a disastrous relationship.

Do you want him drinking and smoking around your kids? Even without bipolar, he doesn't seem to me to be a good choice if you want to build a stable, loving home for your family.

He isn't willing to work on his own problems...why try to take them on yourself? Like they say in AA, people hit rock bottom before they accept help. He sounds like he is well on his way there.

It is different to offer some support to a person who is really trying to cope.