I think I find my boyfriend unattractive
Does this change how you feel about your relationship?
Yes, I doubt we will be together in the future.
Well, if this means you're no longer interested in him then maybe you should end it.  You shouldn't feel like you have to date someone you don't find attractive.
You said that I shouldn't feel like I have to date someone.
Yes, you should not have to date anyone you do not like. Forced interest might make you resent them in the future. Sometimes things just don't work out and telling them the truth would be the best thing.