Well, I couldn't have gone after her when I just broke up, im more frustrated I turned her down at the time because I was with my now exgf because I thought i'd try and fix what was going wrong with it (it couldn't be fixed and we broke up)
I'm just like, why did I waste my time trying to make it work when I could have had this lovely lady
Hindsight is always 20/20. We can play "what if" all we want, but that won't change the past.
Try not to dwell on it too much. Besides, she's with someone right now, so there's not really much you can do about it anyway. Don't harsh her new relationship buzz by dumping the "we really should've gotten together" speech on her. It's not a good look.