14
Conclusion:

After a second (what I thought was great) date, he called and told me he's getting back together with his ex girlfriend. Now, I know this is a mercury retrograde passing fad. But by the time he realizes this it will be too late. I'm not a "plan B".
It seems neptune is the answer- both to your judgement and his attitude and the lack of 7th house influence.
Maybe he wasn't serious about getting into a long-term relationship.

Mercury retrograde could have led to a return to old or restarting communication with the old friend and maybe, your being an astrologer and asking his date of birth etc would have been too much for him.

???

All my chats about astrology are confined to Linda Goodman's sun signs :-)
Anything beyond that generally scares people off .LOL

PD