<human>: Can you condense the text into three sentences or less?

Hi Reddit, 
I'll try to keep this post clear and concise without a huge wall of text (adding in fake names to keep things simple).
Sam and I were on/off hooking up for 2 years.  I moved around a bit and there was a large gap of time in which we never communicated, but I did have feelings for him and miss him.  When he came back in my life (for sex), I confided my feelings in him and it ended right there because he didn't want a relationship.
I was devastated, but then I thought why not try dating on one of those apps and just embrace being single and ready to mingle (since I did want a relationship).  I met Mark on one of those apps and he was perfect in every which way.  We were in love and I thought it was meant to be.  Sam then had a change of heart and wanted his me back in his life (as the booty call obviously) but I declined his advances and told him I was happy in my relationship.  But then Mark started acting distant, and he started confiding his doubts about us in me.  How he feared for our compatibility and wasn't sure what he wanted when it came to us.  Mark never even slept with me or took me out on a vacation - I decided to end things when after a month long break he told me his feelings changed and everything felt forced when it came to us and he needed more "time." 
I feel like I don't know how to cope with Mark's abandonment of me Reddit.  I started going on those dates from the apps and met guys but felt no click with anyone (and the guys I did like didn't feel the same way about me).  And then I managed to hook up with Sam and it felt great to have meaningless sex with him without the feelings -- basically I'm anxious I'm making poor decisions and I sort of feel guilty like I betrayed Mark by hooking up with Sam again but Mark isn't in my life.  I don't know how to cope with this loss. Help
<bot>: Girl feels sad about the heartbreak of losing a guy - and then goes back to hooking up with a former FWB that she had feelings for and even online dating but sucks at it.