Why Scorpio men withdraw ?

So I met this guy online 2 months ago..things have been progressing slowly. We still have yet to met in person but we chat pretty much everyday. It seems like whenever our "relationship" increases in intensity he withdraws for a couple days. But he always come back and actually apologizes for being distant. We both have made it clear what we are looking for and what our expectations are. A few days ago we decided to have a Skype date, and things progressed and we shared something intimate with each other. Now he won't talk to me. I can see he is online and has read my messages. This is so frustrating cuz my ex used me before especially for sex. I was basically emotionally abused by my ex.

Wondering if anyone has some insights on the Scorpio brain when it comes to love,sex,and relationships.