How to ask

Backstory:

Husband had 3 emotional affairs with co-workers from 2019-2020

He has What’s App for work messages/group chats (he is military)

He has been away for a month for school for his new job.

Question:

I still feel uncomfortable/don’t fully trust him again after the betrayal. I often wonder who he’s been messaging, calling, etc. Knowing that What’s App isn’t traceable from our phone plan, how can I ask him to see his what’s app or if he’s talked to anyone with it while away?

He returns sometime this next week and in the past when he’s just come home if I bring any concerns or worries up to him it always ends in a huge fight. He usually something like “thanks for the welcome home 🙄” or “of course you’d immediately start fighting.” And yes, I tried bringing up my concerns while he was away but all that did was left him to hang up the phone and ignore me for a week 🙃

Yes I know this is toxic.