Woman like to get hit on. Remember that. She didn't touch him or kiss him and went home with you. At some point in your life you will grab a woman's ass in a bar when your in a relationship. Does this mean the woman should dump your ass for being drunk and appreciating nature? So before you throw her to the curb think about the things you have done in front of her that she has turned a blind eye to.
On a side note maybe shes a cuckold and wanted to see if you were into it.