I apologize for this being long winded.....but here goes

I am a single mom to a very busy 4 year old boy. He is the extreme of healthy, busy, active, athletic (yes already). His bio-dad is a washed up professional hockey player, and is mentally a total head case. My son has seen his dad physcially restrain me, yell at me, cry all the time, and so on. He remembers having to ride in the back of a police car...anyway, once I finally kicked my ex husband out, I was so afraid that my son and I would sleep together locked in my bedroom (it was the only locking door in the house....except the bathroom). Up until this point, my son had always slept in his own room. We lived like that for a few months, and finally I had enough and moved in with my sister and her family. They had one extra room, so my son and I shared it. He had a little toddler bed at the foot of my bed. My sister's house is usually a total gong show as well. A lot of anger and stuff goes on there, but we were sort of stuck there for the time being. Anyway, I met this guy...he was great. He has twin boys, that are 10, and they are both quite sick. One has cystic fibrosis, and the other is serverely autistic (doesn't eat at all...the only nourishment he gets is from a high calorie formula that is pumped into a button in his tummy at night while he sleeps)...I was so excited because I thought this guy has kids, so we have a good common ground. The time we spend together is awesome. So after a few months, I allowed my son to get to know him, and slowly his kids too. All of the kids got a long great together. We live approximately 3.5 hours apart...so, obviously the kids see each other very seldomly, and the guy sees my little guy maybe once a month...sometimes more, but not that much. I saw his kids every other weekend at least, and sometimes every weekend. I was doing the majority of the driving, and would only take my son there once a month...as I didn't want him stuck in the car that long. He is also only a part time parent, he get's one over night a week with his boys,and get's to see the one boy for a few hours on wednesdays. I have my son 65% of the time...at least. Anyway....that being said, my boyfriend has declared that he resents my son for being healthy, he is jealous of the attention I give my little guy, and figures that because he is healthy, he has no right to have tantrums or to not drop everything and do exactly what I say the very instant I speak it. He acknowleges that this is not fair, or right for him to feel that way, and was trying to move past it. The problem is...that I don't know if I can. I am a very patient person by nature, and he is the opposite. He claims that his kids do everything they are told...but they don't, he seems a litle dileusional in that regard. We broke up for a few months because after he told me all of this about my little guy, I just said good bye, and that was that. so after a couple of months, and us slowly chatting more and more, he has told me that he loves me more than anything, and will do anything to make it work. I do care for this guy a lot, and have never felt like I do when we are together...but, can someone really change like that?? My little guy is the most important thing to me...and he has enough going on with his own dad.... the BF had also comitted to moving up here, until I was in a better position to possibly relocate to his home town, I bought a house (the largest mortgage they would approve me for), because he had comitted to us....then he just bailed, said those horrible things about my son, and told me he wasn't moving. The mortgage is all in my name, so I'm on the hook for it regardless.......i'm so confused!! Is this worth trying to work through??????