if....

if i constantly think about leaving and feel like someone brings no value to my life or growth in anyway and only drags me lower should i leave or stay. Im in my early 20's he is a bit older than me 27 and he believes he is to old to believe he can become anything. He doesnt know how to keep a job doesnt want to go back to school and thats not the part that sucks. Consistently he is out smoking drinking and hanging out with his cousin and friend. He only hangs out with me at night or when everyones busy. He takes all of my money for drugs and alcohol and to eat. I literally have not had money for myself. Also every time i talk to him about his growth and doing better for himself he says at his age its impossible and that he is so old. I feel horrible when i tell him i dont want to be with him but then if i stop helping him no one literally no one will help him and he will be homeless. A huge part of me doesnt care because of all the things he has done to me and gets away with but then i have a heart. He also has cheated on me and ive caught him like 4 times. He has only made me feel worst about myself as a person and not better Am i wrong does success stop being realistic after a certain age? Also he does have good things about him but its rare thats why im confused. Everyone in my family thinks im in a mentally abusive relationship.