I suppose three months woke make a diff... Unless OM is planning to leave his wife too and he just needed time... I woudl NOT have let her out the door to talk to him Ken.. I would have told her it ENDS NOW and that's IT..
FULL TRANSPARENCY NOW... She is very likely going to try to fool you Ken.
Get paperwork together showing that if she is caught cheating you are the primary caretaker of the kids... Any contact and she loses the deal... do NOT take her word for it Ken.
There are dozens of stories on this forum of people who were at your point and they get lied to (myself included), they just kept seeing the OM in secret and hid it much better...