"has had" or has gone out with as in first dates?
Whether this is normal or not... I couldn't say, sounds like he is out to prove something to himself, or maybe he is SA... but I think your focus on it is only going to hurt you. I know my X didn't stop to mourn the marriage either (31 years) but that is his problem. He is terrified to be alone - I'd go as far as saying that he seems to feel that he ceases to exist when he is alone, no one to draw a personality from...? IDK That's not healthy either but it is not my problem anymore.
Keep moving forward StrawBlond. I understand looking back over your shoulder and scratching your head. But putting energy into figuring out your X's malfunction - is wasted effort...