Hopefully you learn to choose a better mate.
When it comes to love and relationships most of us (fail our way) to success. Rarely does anyone hit a homerun their first, second, or third time up at bat. If this were not the case we would all be married to our high school sweethearts!
Oftentimes during our youth it was a case of immaturity and having unrealistic expectations. We really thought we'd found our "soul-mate" at age 17 or whatever.
The vast majority of us at age 28 or 30 look back and see how immature we were. Most people have yet to figure out who (they) are let alone know what they want/need in a mate for life!
We allowed "impulsive connections" and "happenstance" to dictate our relationship choices.
It's the equivalent of going shopping without a list!
Each of us (chooses) our own friends, lovers, and spouse.
With each failed relationship we modify our "mate selection process" or "must haves list" as we discover more about what (we truly want) and learn from bad choices we made in the past.
If you want something different (you) have to do something different. It's important to keep things in perspective.
In order for your (ex) to have been "the one" he/she would have had to see (you) as being "the one". At the very least a "soul-mate" is someone who actually wants to be with you!
Thankfully there are over (7 Billion) other people on the planet.
Every ending is a new beginning!