Why my boyfriend wont step up and be a man?

I been with my boyfriend for almost 5yrs. He has always been spoiled by his grandmother who recently ped away. He never had to pay a bill or anything. Before she ped he took care of her and cared for her while I was pregnant. He lived in the house with her and his father. He was barely there for me throughout my pregnancy. I always lived by myself with my other children that are not his and paid my on bills and everything. Since she has ped he is stuck with the responsibility of paying for a mortgage and all the bills for the house they live in. His father who doesn't do anything lives there now with him. I told him Im ready for a commitment now and marriage. He comes to my house on his off days or whenever he has a chance. He told me before his grandmother died she told him to never leave his father. I feel bad because at first he had to care for her now he has to take care of his father who has nothing wrong with him except he is not working. He thinks its ok to come and see me and the baby on his off day and he really neva has to be responsible for anything financially far as helping me out or spending more time with his daughter. What should I do?