Idk what to do

I (female ) met this girl at a party i went with my friend and my cousin, said girl was with a bunch of her friends. My cousin knew all of the girls including the girl, they started talking i just watched from a distance after the party we headed back to our town which was only about 30 minutes away and they came along, when we arrived back in town we headed to another party. Said girl was already very intoxicated and when we sat on the couch she asked to rest her head on my shoulder i said of course and she did so later in the night she moved into the kitchen with everyone else she sat next to my cousin ( female ) they got told they looked cute together and ended up making out i just moved into another room and i ended up driving said girl and her best friend home that night and the night ended, i thought i’d never see said girl again but she added me on snap chat. ( i met said girl in april ), in the middle of may we were already just snapping eachother and i told her how i felt and she felt the same so we started talking we talked for a while and everything was perfect. On July 8th i asked her to be my girlfriend, she said yes and we started being official, we became inseparable. Until one night when i was spending the night at her house and she fell asleep i suddenly got a gut feeling to look at her phone and i found multiple messages between her and her exs who i was already worried about multiple times before. The morning after i found everything we talked about it and she said she was sorry and so i just left it at that but it lingered in my head. August 28th 2025 i ended up breaking up with her because i felt like i was already mentally exhausted from what was going on inside and outside of the relationship. When we broke up i told her i wanted to stay friends she said that was fine, 5 days after the break up she asked to talk in person so she came over we talked for hours, we talked, we cried, we even laughed and then she said she had to go so i walked her to her moms car and gave her a hug the hug lasted at least 5 minutes it was the longest and tightest hug we gave eachother and when she got in the car i gave her a kiss on the forehead we said we’d wait and fix it. Not to long after i found out her and one of the exs that was texting her were talking and i told her not to speak to me anymore out of anger about finding out this was happening not meaning it, we unadded each other off of all social, shortly after she started dating this ex girlfriend, it broke me inside fully. the other day i seen her for the first time since the last talk and we kept looking at each other and even tho we said no actual words it felt like we said everything with our eyes. October 28th we have now been broken up for 2 months and no matter how much i try to force myself to stop thinking about her and move on i can’t because when i try i catch myself comparing everyone to her. My chest feels like someone is physically being beaten in while i am without her. i can’t seem to let her go and i don’t know what i should do because being without her feels like someone has taken my breath away and i’m im just suffocating, i cant catch my breath because she was my oxygen if that makes sense. What do i do?