Many men are afraid of commitment. That’s just the way it is. Many men don’t want to settle down and even when they are ready to settle down, they’re afraid of admitting it to themselves and to other people.
Society makes huge demands on men, including putting out the idea that men are supposed to be frivolous when it comes to women and date around. It can be difficult for a man, especially for a man that is afraid of commitment, to think of himself as someone who has settled down.
Many men feel that once you’ve settled down, you’ve lost your "spunk" or your sexuality and some men feel that once they settle down, a woman begins to control their lives. We’ve all heard those horror stories of grown men having curfews, and these are things that can cause a man to be afraid of telling their partner that they love them.
Many men feel pressure from society to be "manly" and feel they will be made fun of or ridiculed when they choose to share their feelings.
From childhood, men are taught that they shouldn’t share their feelings and the way society views men that do share their feelings is a hefty contributor to the fact that many men are afraid to tell their partners they love them.
A combination of societal pressure and commitment phobia are huge factors that contribute to the reasons that men don’t say, "I love you."