A pheromone, a hormone, a subliminal signal.
Something I exude.
What else explains it? It starts off slowly, going to bed at different times when he used to drop everything to crawl in with me. A movie on TV is more interesting than the conversation we used to enjoy. Hours and hours on the computer playing games and surfing websites, back turned on the family, annoyed when interrupted, spending more time and effort talking to people online than in the real, live, warm, curious, loving people right here in the same room. Porn sites more alluring than the woman in the next room.
Never reading my words, no longer interested in what I have to say even when it's simply "I love you", looking irritated when I speak and he is reading or typing or playing online.
It happened before...it's happening now...and since I am the common factor, it must be me. I guess I'm just not worth the effort.