I think cold, hard reality hit him once he found out that the family knew what was going on.
It may even have been that he had a fight and she dumped him... There are too many varibles to trust him yet. He can't just walk back into his marriage, he needs to EARN his way back in... he has to do the work before he's allowed back in.
Do NOT have any physical activity with him AT LEAST until you have been fully tested.
I dont' even reccomend it if you are both tested and clean yet.. wait at least three months... the three month no sex rule is a good test of BOTH your maturity levels.