If you're not interested in sex, then could your lack thereof be because of you? For a male to say that is a big thing.
When you stop showing your W that you want to have sex with her, you are showing her that you don't find her desirable.
If that was the case, then it's no wonder why she sought out another man. Without the sex you're just another "friend".
Don't get me wrong. It isn't that I'm uninterested, it's just that sex isn't the dominant desire for my wife. I do show her that I want her and that I want to have sex with her. I tell her frequently how beautiful and sexy I find her. It's just that if I had no other choice but to live without sex in my marriage, I could.
Sex is the easy part. I've had great sexual relationships in the past but I've never had the intimate connection I have with my wife.