New relationship: Should I stay or should I go?

I am a 33 year-old divorced single mom. I have been dating a man who is my best friends brother for about a month now. Him and I have known each other since grade school but I never paid any attention to him up until recently. Since we started dating we have gone out quite a few times and have always had a great time. He is great company, is the perfect gentleman (very attentive, sweet, kind...) and treats me like a princess. We have so much in common and have the same goals and values. To me he is perfect! I have met his friends and their girlfriends in which they have all taken a genuine liking to me and I have known his family for years. He has met my cousins (has not met my parents yet) and they really like him. My problem with this situation is the fact that he is separated from his wife that still lives with him. They split two years ago when he found out that she was cheating on him. She is still seeing this other guy who broke up their marriage while still residing in their home that she shares my guy. I asked if he would ever reconcile with her and he replied very sternly that she is tainted and how he thinks she is so disgusting. He explained the only reason he is still there is because of their 8 year-old daughter. He is an excellent father to that little girl and she is always with him. The mother disappears day after day with this other man leaving him to take care of their little girl. He says he wants to leave her but is waiting for her to get a job because he does not want to pay alimony because she hasn't worked in at least 8 years. So she lives there while he pays all the bills (including her cell phone) and is the built-in baby sitter and runs around with this other guy. She has put forth no effort to find a job and I don't think she plans on getting one anytime soon. I don't know if I have the patience for this situation but I am starting to develop strong feelings and are becoming attached to him and would like to move forward with him.