Well, I consider "cheating" to be a breaking of the rules of one's relationship, not whether or not a couple is monogamous. A lot of couples have open relationships where the "cheating" comes into play if secrets are kept from the primary partner. For other couples, their rules involve asking for permission before any "playing" with other partners occur. Other couples have rules regarding distance, say for example that one partner can play with anyone who doesn't live within a 50 or 100 mile radius, or that each partner may have sex with people only on business trips.
To answer the OP's question, yes, it would make me feel better. I would still be furious and our future as a couple would still be threatened because of the betrayal, but there is a hurtful component to that kind of infidelity that I think I would be spared from: wondering if I was inadequate as a woman and a sexual partner. You see, if I discovered he was sleeping with another woman, I would immediately compare myself to her, wondering in how many ways she was better than me. Is she funnier? Smarter? Have a nicer ass? Is she more seductive than me? Are her tits bigger? Is she a more this or that? If it was a man then I think I would feel that he felt like he needed something that I couldn't be expected to provide him because I'm a woman. I'd still be deeply hurt by the fact that he didn't trust me, he wasn't honest with me, he betrayed our commitment to be faithful, and that he introduced another sexual sexual partner into my life without my consent, so don't take what I said to mean that it would be okay with me. I'm just saying that my anger would be more purely focused upon his betrayal and it probably wouldn't end up bouncing back onto myself and end up damaging my self-esteem.