My philosophy on regret is very simple, and I think it’s helped me deal with it all a lot easier than I otherwise would have and it’s all summed up in a nifty motto: “A regret is merely a lesson unlearned.”
By this, I mean, there are certainly situations in my life that I’ve regretted at times, whether they were chances with women, missed opportunities, poor decisions, or whatever, but time spent brewing on the past is time not spent bettering the present and the future. Instead, I look at these situations and evaluate what I did, directly or indirectly, that created that situation and what I could have done differently. Did I miss an opportunity because I was too shy? Did I procrastinate? Maybe I didn’t take certain things into account.
If I can figure out what I did that led to that situation, then hopefully I can figure out how I can prevent it in the future or what I can do to make it better. And after I’ve learned those lessons, I find that that regret just doesn’t last anymore because without that situation I never would have learned that lesson and become who I am now.
And so, as a result, there were some things that I regretted enormously, even some for a number of years, but now that I’ve extracted some valuable lessons from them, I’m actually quite happy with how they turned out and how they made me a better person. That’s not to say I don’t have some regrets now, but I remain confident that when I do the work to figure out the lesson and learn it, I’ll feel much the same about my current regrets as I do about my old ones.
But seriously, once I figured out that motto and made it a theme for my life, I really feel like it’s not only made those regrets manageable, but made me a better person for them.
As for the OP, it’s hard to say what lessons you could possibly learn from the situation, as it is a very personal sort of thing. As an example, one of my former regrets about a lost relationship ended up being a failure on my part to trust my intuition, another about not being assertive enough and expressing my feelings about her. As a result of each of those, I’ve not only learned to trust my intuition more but I’ve worked to develop it more, and I’ve become a lot more free in expressing myself, not just in terms of romantic relationships, but in all sorts of situations. Both of those have been enormously helpful to improving my life and I wouldn’t trade them back in for either of those relationships.