It sounds like he has some positive qualities but I too would very skeptical of someone who is content to function in a occupational situation where it seems like he is comfortable skating by in this fashion. What if something changes with that couple? Is this experience going to count somewhere else. You have to ask yourself if he has any ambition. It's great that he is nice but is he going to contribute to the household. He could be using some of that time to go to school or learn a skill.
Of course the other issue is this sexual requirement he has. I would have to know if he can be satisified with a sexual relationship that doesn't include this act. People who are about each other get together all the time and choose for their partner's comfort level to give up something they like for the sake of the relationship. How is he going to actt if this doesn't happen. He isn't the deciding vote. He is part of a partnership and you should have an equal say. It doesn't matter about his other girlfriends. They aren't involved. And absolutely you should not be made to feel guilty. I think it should be asked one time and that's it. You shouldn't have to do this unless you are completely comfortable with it. If he can't be satisfied with acts that you can do together than this isn't the relationship for you. It is destined for heartache. You will know how motivated he is to be a couple when you tell him that you won't do it.
If this is helpful press accept