I'm on a relationship and always had interest in older women. I'm 27 and my girlfriend is 55 (she looks around 40ish to be honest).
But I often dream of other women I find attractive (and have desired for), intimate things (like kissing, having sex or just caressing and sharing mutual feelings).
I love my girlfriend and I feel bad for having such dreams when I'm with her.

Am I bound to be unfaithful? Should I ever give up on marriage?