Been there got the T-shirt my friend, but it ain't worth losing your mate over bro! As the saying goes There's plenty more fish in the sea. Dont let a woman come between you and your mate. Yeah he did wrong and probably lost alot of trust when he kissed her, but hey put yourself in his shoes. You woulda done exactly the same, I'd put money on it! Us guys follow our dicks man, don't hold it against him, it's not like your gonna stay mad at your mates dick, coz that would just be weird right?

Peace

Buddy