Check the phone bill and see who he is texting.
Those who have nothing to hide hide nothing.
There can only be one reason for him to do this.
Get an online cell phone account, if you don't already have one, and monitor his texts and calls - who sends and who receives, and do so without his knowledge.
Walk a Mile In My Shoes
Married 14 yrs. Now Separated & in NC
2 grown DD's - his from previous M
4 grown kids (2DS, 2DD) mine from previous M
Let your in-laws know that you are not ok. Tell them what he is still doing. Honey, they already know he cheated. Let them help you.