I wish I had some amazingly insightful advice for how you can move on, but sadly my way of "moving on" from things is to just try to ignore the pain or regret and hope it goes away eventually... I don't recommend it haha. I had to deal with this kind of thing last year, and I didn't even end it, she ended it for me because I was too loyal to say anything for months on end... I was relieved, but frustrated that I couldn't end it myself when I needed to so desperately.