People make mistakes, this is the sort of thing that usually can’t be avoided no matter how hard you try. Sometimes these mistakes end up costing us things that we thought we needed in our day to day lives, things like the relationships that we cherished due to the reason that they allowed us to feel better about ourselves and feel accepted as who we are rather than being forced to act and behaved like someone else until eventually who we truly are simply no longer exists anymore.
If you have made a mistake that has led to your romantic partner not being with you, you would probably be thinking of a lot of ways in which you can get your ex back. This is actually a fairly easy process all in all. The only thing that is required here is for you to be genuinely apologetic and for you to give the person you love the space that they need to heal and get their head straight so that when you do approach them again they would receive you not with hostility but with warmth and the potential to patch things back up again.
If you see yourex girlfriend around town then you should avoid trying to talk to her. Don’t make her feel like you are following her or invading her space. Give it some time try to contact her through a less invasive means of communication such as a text message or a call if you really want to drive it home that you are trying to get them back. Taking it slow has a much higher chance of success than jumping the gun and messing things up further.