I have gone to use DH's phone on WhatsApp and saw there was a woman who's number was not saved in his phone who he'd sent a photo to so I opened it. When I did it was a photo of her which said "thanks" and he'd responded with something work related. I'm thinking there's more to it.
They've only been working together from this week as far as I'm aware (although worked in the same place and knew each other before) but the photo of her with just a thanks after makes me think he deleted the prior conversation because it didn't show one or both of them in the best light. That makes me even more curious because if you're ashamed of it/concerned what your partner would think then it shouldn't be happening.
I don't know how to approach this as he's prone to lie about unnecessary things anyway to please everyone.
Some advice please?