To me it doesn't sound as if your H was coercive -- I don't think someone who had been on the receiving end of sexual harrassment would text the perpetrator asking for "closure"... they would just go running to HR.
I entirely disagree. Much younger people are often groomed by older people who are in positions of power.
Sorry, as for her needing closure. The only thing she needs to close is her legs. - that's absolutely disgusting!
Redwhine - I don't think you are going to be able to make a final decision about this if you are in a middle emotionally. Some people are very confident about what they want straight away but most need a little time to consider things and come to a decision and it is much easier to see things clearly when you are not in the middle of it. That's why I, and other posters, are able to give clear opinions on it.
I think for you (and me if I was in your position) it is important to try and get some distance from your h so that you can think things through properly. So that you are not living in the middle of it and being tossed around like a small boat in a stormy sea. I think you should ask him to leave the house to give you that space for now tbh.
Putting myself in your position I know what I would want myself to do, whether I would be able to be strong on it so soon or not I don't know! It would be over for me I believe.
Instead of helping support you through a miscarriage it appears he has been fostering a highly inappropriate relationship with a much younger woman at work who he has a position of authority over. It doesn't matter how much physical touching happened, it's the emotional betrayal that would matter to me - that rather than be there for me he was seeking out another woman and that the other woman was vulnerable in terms of her age and position at work.
I would never be able to forgive that, it would poison everyone's lives; mine, his and the kids, if we stayed together and tried to make it work.
It is the distance from it that allows me to have my own feelings on it. You may come to a different conclusion but I think for it to be the right one for you you need distance from it right now.
There is no sense in having his phone, in texting her, in desperately trying to find out the truth (which it is unlikely you will ever really know anyway), all that only serves to bring you more into the emotional muddle, I think you should give his phone back and ask him to move out for a couple of weeks for you to have some space. If he won't you could think about having a holiday away from him - just to get some headspace and really think about how you actually feel.