HELP!!

its a shoujo manga (or maybe josei idk) ml and fl are high schoolers, ml is in a music band, he loved an older woman and even slept with her..she also plays guitar, fl fell for ml after seeing him perform (i think) and they slowly got closer (ml still loved the other girl) last i read the other girl was waiting for ml outside his school under the snow, ml and fl were planning to hangout after school but ml ran towards the girl after saying sorry to the fl. (but he ran to her cause he decided to completely end things with her) and fl thought he got back tgt with that girl so she started avoiding ml