Suicidal thoughts

Still depressed over a girl who left me last year . But that’s not the main reason for the thoughts . The main reason I’m depressed is because I was a prick to her then she left bbut she came back few months later after getting dumped by someone else.

So this time I changed I was good to her but she left me again for someone else . Now I keep thinking If I was good to her the first time around would this have happened