I think it would probably be okay to ask as long as you let him know that if he is not comfortable with your request, you understand.
But more importantly, I think that you should trust your gut and just ask her and watch how she responds. I wasted so much time trying to figure out what my WS was doing every time I got a bad feeling, and now I regret it. I think we all know to some extent what our spouses are capable of, even though it's tough to admit. And I think if she is truly remorseful, she will understand why you don't trust her yet.
D-Day3: 7/31/15 Sex with an ugly married Craiglist whore in my home (with my son in the house) DONE!
Blended family with 5 kids
Surprises, I feel now, are primarily a form of violence.