How can I Move on 😞 is that difficulty? I'm trying Hard.

Hi Guy's I'm bisexual so basically I'm in a relationship with a girl that's abt 4yrs relationship we were happy all the time suddenly she finished studies and went back to home town.she told that its okay we will maintain long distance relationship but i felt everything was fine until what happened with a incident it was nothing 😞 I didn't gave attention while she speaking in call wid me the min itself she find the reason told broke up but some how we patch up again when I'm preparing for my final year exams.she told I don't need you lets broke up We will leave as a good friends.the friend zone. Okay i thought i can try to change her through my love and all but she moved on but she gave me false hopes. If you settle I'll patch I'll stay wid you money matters to me.when i joined job i found a instagram acc with other guy.then i came to know she's having bf.then i didn't believe her I thought she's single but no more.when i asked for closure we met restuarant finished talks then i believe that she's not my girl anymore.coz she showed me kiss photos with his Boy friend.After 2 weeks she came to cllg to collect her certificates i told her to met it happened 3 weeks ago then i found a hickey on her neck.it hurts me a lot.. I'm unable to move on.the thoughts memories wid her killing me inside. And she's asking money return which she invested on me.currently they were in livin relationship..it hurts me again.The min I woke up thoughts or else dreams? Please advice me what to do 😭🥲🫠 I'm trying to return her money 💰