DH left his phone on the kitchen table, I heard it beep and saw a number of WhatsApp messages from a woman coming through saying sexy things and then asking him for money. The phone rang (it was her) and I took the phone to him and demanded what was going on. He denied knowing anything about this woman (even though her name was in his contacts in WhatsApp). He called her (apparently) straight back but said there was no answer. He said thought it might be one of his mates winding him up by doing this (they all know he's married).
The day after I told him I was upset by this still and thought it was very odd that this woman is in his contacts but he doesn't know her. He said that he thinks his WhatsApp got hacked. He has 'conveniently' had to change all his passwords. I have left it there but all my instincts are screaming at me that this isn't quite right. We usually have a great, open and honest relationship (or do I thought). I am also pregnant. AIBU to think he's having an affair and what should I do?