Our children have probably learned more about relationships (good and bad) from television and porn. It's part of why all of us are so confused about what makes for a healthy relationship.
This might have spelled the end more clearly than I understood. She didn't want sex. She fought about sex. She complained about how I asked for sex. She always got off when we had sex, but she had started not-caring about the LOVE in the experience. And that was a deal killer, both in the moment and in our marriage.