Ive been with my bf for a yr. he has a 5 yr old daughter who he takes care of everyday. plus he gives his bby ?

Mama child support when she never has her.. if we have plans he sometimes cancels because she has stuff to do... he is also too close to his mom.. nuttin can happened to her cuz he runs to the rescue. When i need something he doesnt hell me at all. He asked me to move in with him n marry him but i dont plan to battle with his mom for his attention... wat should i do???!!??