@Anonymous32776,
No, don't stay with him and no, don't marry him.
You gave your own answers: you're not physically attracted to him, you don't have sex very often and haven't had oral sex in 2 years, only quickies. I assume you're still young and then you have to look forward to a life like this?
No, do yourself and your boyfriend the favor and split. I get that you like him like a brother and perhaps you can remain friends, but as a partner and lover you should seek out someone else. This way, your boyfriend can also look for someone that is more suitable to him.
Good luck!