Get some counselling, Bud. You seem like a good guy. The fact you still love her, after all she did, says your feelings are genuine. You aren't silly for having them, only silly if you act on them.
She had an affair. She worked you over, mentally & emotionally. That's pretty low down on the food chain.
Unless your penis looks like a dried cocktail weiner, I'm sure its fine. Did you worry about it *before* she had the affair? Something to think about.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh