I have. I believe I am polyamorous. However in order for that to work obviously your partner needs to agree with it (mine doesnt) so at that point its just cheating if you follow through with it.

I don't believe my gf would agree to it, either, but it may be the only option now that won't lead to us breaking up. Yet, that may not be the answer for me at all, so I haven't tried asking.

I have always assumed I'd want monogamy, a full committed relationship that is or at least leads to marriage, and that assumption seems wrong now. Patterns from my past relationships are just intolerable, and they have started to emerge after almost a year in the current relationship. I find now that something much lighter seems far more appealing.

How would her not agreeing to it not lead to breaking up if you become actively polyamorous?

I've considered it before but in a very one sided way. I used to tell people I wanted to be like Hugh Hefner and have a few boyfriends at the same time, each wonderful and fulfilling in there own way. I always got laughed at. Now that I'm married I still have these feelings.

NHMedic: I stated poorly what I intended to say. If I wanted to have more than one lover, or just to date other women, it would be best to be honest about that and say so to my gf. That would at least offer her the chance to go on with me in an honestly executed relationship, in whatever form it takes on. I do not expect, however, that she would go for that.

If I am not willing to come clean and tell her that I do not wish for a monogamous, long-term relationship, the only way to preserve honesty would be to end the relationship totally.

It is, and I know from experience, far worse to stay with someone indefinitely when you believe it can't work.