I honestly don't think there is a formula for success vs. failure in any relationship. It depends upon the two people involved, their goals and dedication to one another and the relationship.
That being said, dating someone in recovery has a very unique set of challenges. Not for the faint of heart! My relationship with my RABF works only because we have a history together and I knew him well before his 'bad' days. Without that foundation, I don't know if I'd be as patient. Your situation though is you met him while he was drinking and have gone through his recovery with him. Hmmm.. they say people change a lot in recovery so I suppose the risk would be he continues to change as he gets more recovery time under his belt and wants out of the relationship OR it could make you closer.
In some ways it has been easier being with my RABF than other guys because honesty is part of recovery and not running from problems or feelings is also part of recovery. Meaning when an issue comes up, we work on it and deal with it as it comes.
It is rollercoaster ride, that is for sure. Consider the possibility that he may relapse so then what will you do? How will you deal with it?
Just be careful that you don't take on the role of his sponser or treat him like he is made of porcelain. Recovery is about handling lifes bumps and challenges without turning to the booze and so that will probably be the true test for how 'successful' the relationship will be.