I would not call him a sicko or pedaphile just because of the physical reaction his body has given him... but I would look deeply into the WHY for it and with that therapy should be sought to get to the bottom of it all.

IMO - I think your husband left due to the fact that you caught him at some thing he him self is confused and ashamed about and probably has been for some time.... hence his retreat to safety at another place, far from you and the object of his confusion.

Please know that you did nothing wrong and have nothing to be guilty about - safety of the children comes before any thing else - ((( HUGS )))