Hi BS08,
I know the sort of pain you mean and I'm so sorry for the way you're feeling. I'm eight months out and the sting is out of the tail of it now, though I've had my ups and downs. He ended it, there was another woman and it was rough, rough, rough in the beginning. I don't know about concrete tools but I can tell you what worked for me.
1. Al-anon - and I got a sponsor at my second meeting. Over the months I looked hard at my family background and my dating history - it became clear that this was about way more than him, which helped take the focus off him. He's a small part of a big picture and that was the start of getting some perspective.
2. No contact. I called him once, about a month after things ended (he called it off by phone after a year together and that was that). One call was enough - same circular crud on his part that had turned my head inside out at the worst of times. I have totally avoided anyone who might know what he's doing, or how he's doing, since around the same time. This has meant turning down invitations, and even changing my route to work - and it's worth it. The one time someone felt the need to let me know how gaga his new girlfriend was about him, I was a wreck. If you can, I would highly recommend taking a break from mutual friends who will let you "catch wind" of his romantic trips - that stuff is painful.
3. I made a list of all the worst of times, chronologically. Times he had let me down, caused a crisis, gone M.I.A., pulled a stunt, been passive aggressive, or said something hurtful. Times I had lost sleep, paid his way, made excuses for him, changed my plans to accommodate him etc. I was really, really thorough and truth is that it started pretty early in the "honeymoon" period. Even the "good" times actually came with a big, heaping, helping of stress. I read that list often in the early days - or when I started obsessing about how happy he might be.
4. When the worst of the circular thinking was over I stopped analysing and what-iffing and I let myself be honest to god sad. Sad that it wasn't what I hoped it would be, sad that I loved someone who didn't or couldn't love me back and sad that I hadn't taken better care of myself in the relationship.
5. When the sad was over with I got very, very, very angry and I let myself feel that too.
6. I started reaching out to old friends to remember that I had a history long before him and that I'm a whole person lucky enough to have people in her life who genuinely like and respect her. Having people treat me with honesty, respect and care was really important and every time I had an honest interaction or a moment of connection it built me back up a little.
7. I read, read, read and read the boards some more as well as a tonne of literature. And I started to realize that, inherently, anyone who doesn't want to be with me - no matter what the reason - isn't the "right" person for me. I had some amazing moments with my ex and the personal chemistry was pretty unique. Doesn't outweigh lying, cheating, manipulating and picking alcohol over me, his family, work and taking any kind of responsibility for himself.
Sorry this is so long - I think that Al-anon and serious no-contact are the biggies. I also took on some new clients and have been really challenged at work - also great for the self-esteem.
I hope that things start to get better soon,
SL