Infidelity

Maybe because he is self-centered and enjoys chasing other women and has no desire for a committed relationship.

The better question is why does a woman who knows a man is this way continue to put up with it instead of kicking him to the curb?

'Why would a man go way out of his way to hide chasing other women from the start?'
The key here is 'from the start' but how about 'one time he did treat me good'?
Where is the truth? Are you kidding yourself? Had he ever treated you good?
Maybe just to get you in the sack? And after...went on chasing other women including your friend.
PLEASE, PLEASE, PLEASE, dear my honey, baby, darling...find yourself another man. You know it and it is hard but you don't want to sit here for years complaining about same man same problems and god forbid with his child in your hands. Good Luck!

He may not be looking for "something better."

He almost certainly is looking for "something different"...whether it is better (in the sense of your question) or not.

In the main, the "different" is what makes male orgasms more intense...more pleasurable. And more intense...more pleasurable orgasms are something much sought after by men.

Not sure how it is with women.

Is intensity of the orgasm depends on a woman or state of the moment?
Like if man being 'in the mood' or caught off guards, or something else?
Can one man have different intensity with the same woman? I always thought he can. And does.

I was not directing my comments at that, Eliusa.

I was merely noting that Freedom was suggesting that the guy was looking for 'something better" when that might not be the case at all.

He may simply be looking for something different...which, no matter what you may think, is a huge stimulant for many men.

From the other things Freedom mentioned, the guy may simply be an unthinking, unappreciative jerk off. That is for her to decide...and to handle.

But being attracted to other women...and hiding that fact from a loved one...

...is not very unusual.

He's bored, he likes the chase, there's no challenge, he's addicted to the feeling he gets when he's on the chase . . .

Break up with him. He'll love trying to get you back. Make him miserable.

He's s sick SOB . . .