The Ed med may help,you also need to think about the fetish that turns you on while you are with your girlfriend. I don't know what your fetish is but maybe the girlfriend wouldn't mind it and do it with you. Look,I don't know your age or if your indulging the fetish with a Dominatrix or just looking at porn. If you are just looking at porn try stopping for a couple months and focus on relaxing with your girlfriend.