I agree with the letting someone back in too early... I just don't think they get the full effect of what they have done. I think it is good to let them sweat. I think my WH sweat some when, during his first A, I was seeing a L and would no longer let him in the home based on the L's advice over WH abandoning us. I contacted the OW, and after a couple times, she freaked out and backed out of the A. So of course, my WH came crawling back around and I was so afraid he would go out and start a new A, that after a few hours of talking, I let him back in our home and we began piecing with a MC.
My MC told us it was normal for me to have questions because I had been through a traumatic ordeal and he should answer those questions, even though it was hard, because it helped establish trust. MC told my H to be patient while I learned to trust again, however long it takes He seemed to do this only days, before he felt like I should be over it.
We continued to piece until we got comfortable once more and he abandoned us again 11 months later.