Why do men lose interest in sex?

1. Passivity in life. If a man spends most of his time lying on the couch in front of the TV and is not active in life, then he is likely not very active in his sexual life either. 2. Physiology. If your man used to exhibit sexual prowess in bed but now avoids spending time in bed together, it does not always indicate infidelity or relationship problems. A woman should gently discuss the topic of reduced male activity. The issue might be due to malaise or a urogenital disease.