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

Ok, so to start I'm a 22 year old male dating a 22 female and I have been dating this girl on and off since 2010 we broke up twice because I had suffered from depression and didn't want to drag her through my self hating stage but I'm all better now :). 

Anyways we've been back together since Fall and now I'm not happy, I don't really want to be with her any more but can't seem to pull the trigger on breaking up with her. Which is strange because I can be a heartless ass sometimes I made a pony cry once ( I know unrelated but it's a funny story).

Then to complicate matters I can't stop thinking about my ex that I dated in high school and a little trough college and that really confuses me because it's been so long since we dated and I haven't spoken to her in a year. 
Reddit what do I do? I kind of want to be with my ex but know I shouldn't so I'm very confused and I'm scared that if I leave my current girlfriend I won't find someone to be with because I do want to get married and settle down. So pleas help!
<bot>: Unhappy with current GF, started to have feeling for Ex-GF, scared I'll be forever alone if I leave current GF.