Woah! Slow down girl!
That there is someone, or something "karma" out there trying to get you for leaving the past bf is, well...a little crazy thinking. No disrespect intended.
I understand how you got there, I have done it myself, but it is simply guilt that you are still carrying around for leaving that guy, and/or, a belief that you had a choice between two guys and you chose the wrong one. You hedged your bets--we all do--and it didn't work out--accept that, and then you can move along.
36 is young. You may or may not have children in your lifetime, but you still have years to work with that dream.
One word of caution--find the right guy, not simply a guy that wants kids (ignoring other issues and making a deal with the devil).
A hard life of lonliness in front of you?
Why would you set yourself up for such a life? Thinking along those lines will make that the result.
How about a little optimisim for your future!
You're young, gf. Between the ages of 36 and where I am now...I have lived several lives.