Despise my step son

And I feel so guilty about it! It's like whenever he's around the joy just sucks out of me. He's 15 and is so disrespectful and has a mouth on him. His own mother can't even stand being around him. He has purposefully broken my daughter who's 4 toys. He talks back all the time. I used to only have to deal with him every other weekend but his mom recently dropped him off and hasn't come back. Nobody can get in touch with her. Everyday I come home I hope he's gone but he's still there. I came home yesterday and he was lying on my husband's lap and my husband rubbing his head and my husband said to me "His mom's not coming back". I'm pretty much stuck with him now. It makes me depressed. My husband said he can tell how much I resent him when his step son is here. I told my husband because his son talks to us however he wants and has no respect and he needs to do a better job disciplining him. My husband struggles with discipline because he was abused and he always said he would never lay w hand on his son which I don't spank my daughter so I understand but he is so worried about traumatizing him that he hardly disciplines him at all. I'm just tired of feeling depressed in my own home. Since he found out his mom isn't coming back he's mainly been hanging around my husband so I haven't dealt with too much so far today. But I don't want to be uncomfortable in my own home. I don't want to be depressed. I don't want to resent my husband.