Men reaching 40 notice they're not what they used to be. They get some kind of revelation and get depressed because of multiple resons: hair loss, sleeping problems, erectile dysfunction and virility problems and they fall further into depression. They get cranky, feel less motivated and often they will experience the same symptoms as a woman reaching menopause: flushes and sweating, beside loss of muscle mass and strength.
Andropause
This is the omologue of female menopause, meaning reaching the end of sexual life, with diminished sexual craving, gradual loss of testosterone (10% every 10 years after reaching 30 years of age) and mood changes. Men usually get depressed rather than doing something about it because they feel they reached rock bottom and they feel no motivation of doing something else to fill the void.
Solutions to this phase of life are watching your diet, get regular exercise, reduce tabacco and alcohol intake, and increase sexual activity. Spicing up your sex life may get you out of this pahse, but cheating on your spouse may not be the best solution to this. Get some action in bed with your wife, spice things up with her and you'll see your relationship will only benefit off this.
