Help with cheater

So I’m married now but while we were just dating a year he cheated we broke up and he went for two months the other women. He eventually realized he missed me blah blah blah. I took him back then we later married. Well fast forward today his phone was hooked up to the Bluetooth in truck he got out I was still in there and he apparently went to Snapchat and who’s voice do I hear!? Hers and I know it was hers because she said her sons name several times. What would you do?

Like I said we are now married, I have 3 kids who look to him like dad, we have pets together, we have joint accounts, also recently purchased a house that I couldn’t afford on my own. So now what next? I’ve told him before to delete her she knew about me when she got with him before so clearly doesn’t bother her to be the other women