Don't know how to react

It's not my nature to go thru my boyfriend's phone...but d first tym I did I nearly died of a heart attack.

We travelled out of town for an occasion, stayed in a hotel...we were having fun nd it was beautiful until I went thru his phone while he was asleep cos i couldn't sleep nd saw he had a friend who is in a different country that he constantly chatted with like they 're dating...he tells her all he's doing nd abt yo do including our trip but I wasn't mentioned in all. The chat went as far him saying it's been 5months now nd he thinks he's gonna impregnate her the next tym they saw, he wants to meet her mum nd all of dat shirt...he even sent pictures of him he sent to me to her.

When I confronted him he didn't apologize, he told me he just flirts nd nothing more...they were sexual innuendos dat he didn't fuck anyone nd ended it by saying if he ever finds such messages in my phone...he won't forgive. Am confused