Ive had two back to back serious relationships. Although there was never cheating involved in either i can relate to your experience and want to offer advice.

I loved the first, head over heels and she broke up with me. that led to me kind of rebounding into the next relationship. 6 months into that the fist begged me back saying she made a huge mistake. i was spiteful and at the time thought i was happy in the new relationship. another 6 months and i realised my mistake with the rebound, we were not right for each other, i broke up with her and then tried to get the first girl back only to learn she met someone else who she now claimed to be in love with.

this was a year ago this month and, through a lot of regret, confusion and then with advice from a very wise friend i realised the first girl never loved me, she loved the security of being with someone (which lead her to rebound herself). This realisation was a complete cure for every remorseful feeling i felt and i know now without a doubt that a relationship can only be healthy and work when the two people love each other for who they are not because of the security of being with someone.

You WILL find someone who loves you for who you are. It can never work if one person is unsure, it can mean they are keeping it going for the sake of being in a relationship which is what they want more than the person they are with.

true love is out there, you just have to go through some obstacles to get there. time will heal and if you convert your negativity into a positive attitude you'll get there and you will ironically value the bad experiences for leading you to the good ones.