Your friends say that you are [due to the way you think] "a woman trapped in a man's body."
Let's examine that a bit. They seem to be implying that you (a man) think in terms traditionally and culturally
attributed to women. So, what they are really suggesting is that women (primarily) are more likely to be faithful
in relationships because they are more honest and loyal than men. That, of course, is a fallacy. Ironically, they
are also implying that you can't just be a man with certain positive morals; which alludes to their warped sense
of what it means to be a man. For the record, ALL men are NOT unfaithful and ALL men DON'T have a disloyal point
of view or disloyal tendencies. Making that generalization is no better than the dangerous generalizations
attributed to "Black" people, women, and homosexuals.
The other danger associated with that false generalization about men is: If women (or men) actually believe it, they've accepted it as something that can't be modified. If that's the case... They program themselves to accept cheating and they'll allow emotional abuse and [in many cases] open themselves up to potentially contracting an STD because they expect their mate to cheat and they lower the standard of accountability as well. Again, ALL men DON'T cheat! Don't expect it, DON'T accept it, and DON'T think that you can't do better if it happens to you.
HONESTY is very important in a friendship and in relationships. I advise you to be honest with your friends about what is going on in their relationships. Treat your friends the way you would want to be treated if you were in the same situation. I'm just assuming that you'd want someone to let you know that you are in a relationship with someone who is unfaithful to you. So, be the person you want your friends to be to you.
You aren't being unrealistic. You and I are similar to the degree that I too am an advocate for relationship fidelity. Honesty, healthy communication, and loyalty are keys to a good long-lasting relationship. People who can't be faithful are UNSTABLE in multiple ways, on multiple levels. The root of instability is dishonesty with self! People who can't be honest with themselves and haven't dealt with their unresolved issues won't be honest with others. But, you'll only be able to acknowledge their issues if you spend enough time [Redd's estimate: at least 2-3 months] with the individual before getting into a relationship with him or her. So, consider this [advice for yourself and your friends]: when we date [or "talk" to] a person for a short period of time, usually the length of the relationship will reflect that. In most cases, the relationship is short because very little time was invested in really getting to know the person beforehand. You asked about reality verses being unrealistic... The unrealistic supposition is expecting to spend a lifetime with someone you've only known for a few weeks. That is possible on television and in the movies but we'll fail when attempting to incorporate such fantasy into our reality.
From my lips to your soul...
Redd