Todomomo

Momo might've dated Awase but it didn't last long.
She was Shoto's first and only girlfriend.

Kirimina

Kiri has like two girlfriends, Mina had a few boyfriends in Middle School.

Miruhawks

They both had their fair share of girlfriends and boyfriends. Rumi has four ex's (one is still salty), and Hawks had like seven.

Iidamei

Neither had anyone.

Kamijirou

Denki definitely had at least two girlfriends in middle school, Jirou probably didn't date.

Dabi x Toga

As Touya, he was pretty popular and has a few ex's. Now he's Dabi and he has a lot of ex's cuz that man is a heart breaker. (not for me tho, he loves me-)

Toga didn't have anyone.

Nejitama

Nejire had at least one boyfriend but got rejected a few times.

Tamaki didn't date, too shy.

Mt.Kamui

Too many on both sides

Ryushot

Ryuko probably dated Hawks for a few weeks as a joke. Like "bruh my ex won't leave me alone, be my girlfriend for a second" and they broke up a few weeks later cuz they forgot they were fake dating and had to officially break up. But yeah she's dated like three other guys and then settled down with Shinya.

Shinya probably had one girlfriend that was only into him for the fame.

HitoRei

Reiko probably had one boyfriend but it didn't work out. That was her rebound while she waited for Shinsou to be ready to start dating. (She didn't like the guy at all, she just wanted love-)

Tetsukendou

Kendou had one guy but that's it. Tetsutetsu didn't date, he had crushes, but didn't date.