Regarding this weekend, she has decided to not go to the wedding shower, but has said she may be visiting friends while I'm out of town for my event. Would it be reasonable transparency to ask her to call to check in with me and send me selfies of her with her friends, or would that be smothering/controlling? Would it be inappropriate for me to ask her to come to my event instead and avoid any solo stuff for the moment?
Being alone, with you out of town for the entire weekend, is not a wise decision. The fact she is pulling back some, is a sign she needs to be monitored. If she doesn't understand how she will experience withdrawals from the OM.......and if she doesn't understand what is required of her at this time.......I think she will refuse to cooperate.
If she won't go with you, then her sending selfies with her friends (and not old one) is one way she could account for where or who she is with. Do you know these friends? Do they support her affair or that lifestyle? Will she be going where she would see OM? Three weeks is just about right time for the cravings to really start bothering her a lot.
You really must explain how things have to work until she is through the withdrawals and is earning your trust again. Do not put this off!
Btw, an unlearned WW will accuse her H of controlling. You must not let that bother you. She doesn't want anyone in charge, but if the H doesn't take charge, the MR will be in the toilet.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!