My husbands cheated our whole marriage should i stay or leave?

I've been married for over a year now with my spouse. We have 1 kid and another one on the way. He's been acting really funny around me lately he's always going to the bathroom with his phone. When I ask for his phone or have it in my hands he would get angry. Not only that we argue almost everyday. Last week on Friday around 11 almost midnight there was a text I suspect it was a female she said hello babe what you do today babe. I confronted him about it and he said he doesn't know who that text message is from. He was consisted that he never seen that number before. I checked his call log he called the phone number before 04/19 told me he received a text from the same number and tried calling to see who it was. I'm not sure what to do with him. He's so hard to talk to has a nasty attitude towards his family and mines. He's cheated on me throughout our whole marriage and he tells me he loves me but I'm blind to it because I love him he's the first man I've ever been sexual with I think that may be why I'm always taking him back. I'm numb to it all. We're trying to work things out for the sake of our son and our second one coming.

He's also been going on Craigslist seeking out other women to have sexual intercourse with. I know he may have met with one lady that he paid. But everytime I bring the past up he gets angry. I don't know what to do should I leave or stay?