Without actually knowing the dynamics of your relationship and her's to him, it's really hard to say.

Given this day and age where everyone seems to hold no loyalty to anything except their private parts, I think you probably know the answer. But perhaps she is just friends with the guy. Sometimes people are able to remain friends even though the relationship is over.

The unfortunate part is that women generally are more cunning and manipulative than men and have capitalized on men being dogs for so many years. You did say it's been 7 years that you've been with her and that is about the time when relationships start to fall apart.

Sorry to hear of your problems man. Hopefully you'll find someone that better suits you and your core beliefs in the future.