He is clearly under a lot of stress, and that stress seems to be what has caused him to "decompensate" psychologically. I doubt, however, that his psychotic delusions are totally the product of these stresses, serious though these stresses are. He sounds like someone with very substantial underlying mental illness. What has happened over the past year with the ex seems to have exacerbated a problem that was merely dormant for the first year of your knowing him. Even if and when he sorts things out with regard to the ex and the kids, other stresses will come along in life. You have to wonder if this is who you want as the father of your future kids.

This is not a man who copes well with adversity. Thus, the recent drinking. He sounds fragile, psychologically. Joining you to realize your dreams and aspirations probably feels overwhelming to him right now. He may never feel ready to undertake beginning a new family. It's awful tough to give up on love, but he may lack the capacity to be who you need him to be. Partnering with him may be like adopting an older special needs child. Many years ago I did that, myself, and I'm living with the consequences. It's not something I'ld recommend to a healthy 22 year old with all life's possibilities awaiting her. This might end up being very unfair to you. You could spend your life paying for his mistakes.