Help.

I'm in a relationship for over 4 years now. I love him to death, but I've always been sexually attracted to women. My bestfriend and I fooled around once, but he didn't like it. He says he doesn't want to share. Should I cover up what I like just because he doesn't want to share? I've been having dreams about sex with girls lately and want more experimentation, but I don't wanna feel like I'm cheating. Advice please. Also no judgment please. Thank you I'm advance!