Beast, my first thought reading through all this is that we have some amazing people on 11W. You have already received some very sound, thoughtful advice. As a woman, I can confirm that we appreciate confidence and stability. Neediness and desperation don't play well, so working on yourself and finding what makes you tick is key. I believe that if you treat people well, if you surround yourself with friends and family who care about you, if you do something that brings satisfaction at the end the day, then you will be fulfilled, and yes, happy overall. Not all the time, because life has definite ups and downs, but enough. Invite a co-worker to lunch. Visit your folks. Volunteer at Habitat, or be a Reading Buddy. Run a 10k. Just do something fun with a couple of friends on the weekend. It all adds up. At some point you will feel better about yourself and your prospects. You will be comfortable in your own skin. We can smell a fake a mile away, so be yourself. Your best self, but genuine.
I don't know anything about the woman in question, except to say that she wasn't a match. You have been grieving the loss, which is understandable, but at the end of the day, do you want to be with someone who has decided you aren't the one? Change is hard. It is one of the reasons individuals who are divorced sometimes get back with their exes again and again. It is comfortable, easier, even if they aren't good together. Sounds like you are doing the right things. Work on you. Stay active. Become a better family member. The older you get, the more you will appreciate them.
Keep us posted. I'm rooting for you.