when you wanna fuck him but he has a gf

so i met this guy a few years back, when i tell you he is one of the sexiest men ive ever seen ESPECIALLY in the city i live in, he is soooooo fine.
& we would run into each other often bc we had mutual friend groups but we never flirted or anything. we followed each other on instagram for a while, we never dm’ed or liked each others stories.

i saw on instagram that he had a gf, who also he had a kid with!! so i definitely didn’t want to step on any toes. HOWEVER. i’ve had about maybe 4 dreams of us having sex, & his gf always near by trying to find out who i was.

so a few days ago…… he messaged me on instagram. late night, WHAT IVE BEEN WAITING FOR. obvi a bottle call, but i’m fine with that. sometimes casual sex is just off of pure atttacton. he wanted to hang out & he said he’d drive to come get me. i was sooooooooooooo tempted. bc ive had a crush on him for a few years now lol. not a serious crush, but like he’s just my type & im really attracted to him. i would love to experience having sex with him. but i declined the offer bc he has a baby mother.

he doesn’t post much of her on his page but i found her instagram & she has way more of him, so i just honestly felt sad & didn’t wanna cause to her pain bc that right that shows an imbalance.

but part of me was like ugh i kind of want to just be selfish & do it bc that’s my opportunity to fuck hum lke how i’ve been wanting to since we met! but i felt bad.for his gf/baby mom.

if he’s ever single again soon & hits me up i’ll definitely do it lol
what would you guys do?