If my Wife cheated on me, Me forgiving her would depend on several reasons. 1, Did she use protection? 2, Did it happen once or more than once on several occasions? 3, Being Drunk is NOT an excuse, if your so drunk your comotose, then its considered Rape because consent cannot be given by someone whose unconscious. 4, Did she have the "balls" to tell me to my face, or is too chicken and uses email/text/phone/post etc. The fact that your GF is pregnant, changes things completely. She went out with the "mindset" of being unfaithfull, The time between getting drunk, getting chatted up, deciding to f*ck her new friend and then going somewhere to do the deed was not just a few seconds or minutes, so its not like she didn't have time to change her mind. A woman who is happily in a relationship, does not just decide on the spur of the moment to have sex with some random guy she meets whilst socialising. It hardly matters now, but she was obviously lacking something in the relationship, whether that was Good sex etc, but she still cheated, got pregnant and now you have to walk away and leave the b*tch too it. If you Love her its not going to be easy to leave her, But for your own dignity and self worth, respect etc, you have to put her out of your mind and get her out of her life. She's too immature to carry on with a committed relationship and will CHEAT again at the drop of a hat. (or the drop of a few beers).