Guys with a side girl, why?

Why seek another girl other than your current relationship? Maybe not a relationship, but why choose to look for another girl to have on your side when you already have someone?
Is it because the one with more stability is lacking something? Is it because you can easily obtain it?

I have someone in my life who keeps wanting me, wanting to still meet, even though he is in the process of making this other girl his girlfriend.

Curious to know why he keeps coming back for more but won’t let this girl go.
Before being shamed, they aren’t in a relationship. And if they were, I wouldn’t even listen to him.
Guys with a side girl, why?
Add Opinion