Messed Up Priorities--Do you really have to watch Sports Center again at 11:00 p.m.? You had a window and it slammed shut with your wife's tired eye lids. Get the kids to bed before your own bedtime. Putting kids to bed at 10 or 10:30 makes for sexual frustration. You're just too tired to do it. Turn off the TV, the computer, the book, the phone calls, the kids, the housework, whatever, and get in bed in time to have sex.
You Hate Your Lover--Oh, you don't want to admit it, but there it is. Sex requires a certain amount emotional engagement. Some men and women find themselves nearly impotent because they cannot imagine having sex with him/her. Their drive is gone. Men are as prone to psychological impotence as women, here. It's called unresolved anger. Find a therapist and resolve it.
Masturbation substitutes for the real deal--It's faster. It's easier. It's less demanding. It can be fit in to the routine. It's convenient for the emotionally stunted who have trouble in a mutual relationship. Whatever the issue, it's a substitute. Maybe it's not no sex drive, maybe it's misapplied sex drive. If you're in a relationship, it's unfair to divert the attention away from your mate.
Check out Melissa's blog for more.