You seem to take an awful lot of responsibility for what other people do. If I read you correctly, you think that a grown man who never had a real life relationship left you after six months because of your behavior. I'd say it was very likely to happen and I doubt that he will be able to hold on to his next few relationships. It's not what you want to hear, and I'm sure you had good moments with him, but it seems to me like you dodged a bullet. Having him return doesn't sound like a good scenario for you, not for your next 50 years. Anyone should have higher standards for a relationship than someone who never says I love you in six months and is bothered to even share what he does. You were not asking for too much and, even if you were, you should find someone who's willing to share as much as you will. Set your sights on this.
The larger issue remains this impression that you can control your relationships if you just act right. You don't. People have free will, they have issues, baggage, desires, wants. And it changes all the time, sometimes during a subway ride, sometimes at the top of the Kilimanjaro, sometimes while we sleep.
It seems to me that you have a great opportunity to work on yourself, maybe better than at BD. I'd venture to say that the pain you feel right now is mostly due to your personal issues, more than the loss of a particular relationship. This idea that it's all your fault, it needs to go. This idea that things can be guaranteed for life, it needs to go. This idea that making love with someone is giving away a part of you, it needs to go. This idea that you're looking for a needy partner, it needs to go.
There are far needier people than you out there who are in committed relationship. And many independent people beyond your imagination (separate houses! separate holidays! open relationships!) also. Your basic problem seems to be self-acceptance. Once you're comfortable with who you are, you can look for someone who matches, rather than going after a generic profile of a needy person that is unlikely to leave you for lack of options or courage.
Have you read Codependent no more? I haven't but it seems often referred to around here and maybe it would be relevant to your current situation. Don't waste this crisis.
M39 D6 D3 (at S) S 2014-09 D 2016-09
"You can't start a fire sitting around, crying over a broken heart" - Bruce Springsteen.