Thank you all for your responses. In reading them I see that I had only given a small part of the story, so I'll fill in some gaps...
Though I did not recognize it at the time, our relationship had become toxic, on several levels and for several reasons. A large part of that was my fault, and I have acknowledged/confessed/repented of my wrongdoing - to her and to God. For the first year after we split, I prayed, hoped and asked for reconciliation. She made it clear that she wasn't interested, and pushed for legal separation and later for divorce. I sensed the Lord confirming that the marriage was over, which gave me the peace I needed to accept her demands.
I have sought and continue to seek godly counsel, from Christian professional and non-pro sources. In among the other necessities of life, I have been learning all I can, identifying and dealing with my own sin and pain, and forgiving her, of course. Throughout the process my prayer has been along the lines of, "Lord, please change me and make me whole; make me the man You want me to be. Let's deal with
all my junk!" Romans 12... 'be transformed by the renewing of your mind.' Yes, Lord!
I was talking through this with a friend yesterday, and concluded that the two biggest things I'm processing are that there was no clear biblical warrant for divorce (no adultery, that I'm aware of). Her having a boyfriend now changes that, at least by perception. However, as mentioned in the responses, I need to be sure the Lord says I'm free. Also, I want to be pretty certain that I have identified and dealt with all my hurtful habits. I have no desire to inflict them on another person.
Thanks also for your prayers; much appreciated! And thanks for being the kind of people who affirm, encourage, and edify; I am blessed by it!