Help! I dont like my step son...

karen
I feel really bad about this, I do. My boyfriend and I each have a kid from our past relationships. We've been together for 2 years. My son lives with me full time hes 3 1/2. His ex took off with his son when his baby was born and after him fighting her in court he finally starting getting custody of his son. His son is only 9 months younger than mine. I love my boyfriend and we've been wanting a baby together for a long time. The problem is is that his son is a terror. I feel that he might be autisic because he is showing signs of it and needs to be further tested. Currently he is speech delayed, hes over 2 and a half years old and is in speech therapy because he can not talk at all. I understand that he has problems, but during my boyfriends custody time with his son, he is constantly causing havoc. He bites my son, throws rocks at him, spits on him, my son is constantly crying because he cant go 10 minutes without my boyfriends son doing one thing or another. He screams and cries, constant meltdowns, bites, spits, throw personal items down the stairs, bangs toys on the drywall, its a nightmare. Because his son cant communicate he does not understand me when i tell him to not do things ie biting, nor will he even make eye contact with me. I dont know how to handle his son. I never had to deal with a kid on this level before. Its hard showing affection to a boy thats constantly hurting my own son. Sometimes I feel that it would be better to get out of the relationship if I can not handle the situation, but i really love my boyfriend and want us to have a child together. If I have a child with my boyfriend I know it means I will be stuck in this terrible situation. What do I do?