I know some will comment about possiblity of OP but I don't think so. And I also figure if that's what she is doing it doesn't change anything anyway so it's none of my concern.
How sad. One word to describe you is NAIVE. How can you continue to be so naive?
It DOES change things, but if you want to believe differently then so be it.
You are ENABLING her.
Very sad to watch you continue to go through this and be so naive about affairs and women. She will never respect or love you back as long as you keep allowing her to pull the wool over you eyes so easily and refuse to get some backbone. What you have been doing for so long is NOT working. Please admit it and try something new and different.