You correlate the porn with your bipolar disorder; do you self-medicate with porn as an antidepressant?

If the porn has really taken hold and irreversibly conditioned you to crave a rapid procession of intense and different sexual highs that could never be matched by a real relationship with a single woman, then no one will be capable of turning you on sufficiently for very long. If you can't leave the porn alone and you can accept this destructive conditioning as a consequence, then the way you experience sex and sexual attraction has been altered: stay with the girlfriend that you love. The porn will always be there, sexual attraction is common and love is rare. Isn't this why people swing? Have you brought up swinging with your girlfriend? We live in an epidemiological ocean of incurable and/or potentially lethal STDs, but what the hey, right?