You're 28, you havent had sex with this man but have fallen in love with him in your mind.
You still have the power to get out of this situation, YES it will hurt like hell breaking it off with him but it's inevitable at some stage you are going to get hurt and have to end things. The longer you leave it the harder and more hurt you will experience.
Ask yourself this... Do you want a normal marriage/partnership? Do you want kids? Can you have any of this with this man?
Think for the future not the present and I'm sure the answers will stare you in the face. It's really only about recognising a bad situation and being strong enough now to get yourself out before you really are in too deep!