Need advice!!!! Cheat or leave?

My husband watches porn all the time but won't have sex with me unless he feels like it. Then when he do he goes soft 2 mins in. The sex is not enjoyable 90% of the time because he either goes soft or doesn't do any of the things I'm used to like foreplay or oral. 

I'm at my wits end. I've have asked him does he not find me attractive anymore or if he wanted to just call it quits. He tells me no and that I make our whole marriage about sex. I don't feel like sex is the whole thing but when mostly everything else is bad I need something to be good. The only thing I can say good about the marriage is he don't cheat and he doesn't hit me. But he is lazy around the house, barely work and puts everything on me. 

I've asked for a divorce because I don't wanna cheat on him but he won't give me one. He said he will only leave if I cheat but that is not something I think I can live with but lately I feel like I'm getting closer and closer to stepping out on him. I would love for us to get back to where we use to be and love each other deeply like before. But i don't feel that anymore nor do I feel like he appreciates everything thing I do for him and our household. 

What should I do? I'm open to any and all advice. 

Sorry for long rant 

- Tired wife of lazy husband