If you are in a bad or unsatisfying relationship, it would be no wonder that sexual interest would diminish. Sometimes the hardest thing for me as a sex therapist to figure out is what came first, the lack of sexual desire or the depression, because some people get depressed because of the fact they have no sexual desire. The reason your husband would do this is because he is a guy. That is what guys do. We have a million years of evolution and neurological hard wiring that say we respond to visual stimuli.
Women typically respond to auditory or emotional stimuli and that is why women read romance novels.
I suggest you talk to many of your guy friends and ask the same question. Touching other people is a whole different story. Foreplay is defined as everything that occurs before intercourse such as kissing, rubbing, licking, stroking and maybe even oral or manual stimulation. I much prefer sex play because that can consist of lots of things and can occur before, during or after intercourse. Both male and female genitals go through many different things.