Sexting, cheating? Ok after?

I personally feel like any form of flirtation is cheating. I've only caught him the once sexting. I was devastated. We have 3 kids, 4th on the way. I know he watches porn but didnt know to what extent. Now to find out hes been on single apps "lookin for nudes"

Whole social media account i had no idea existed and he showed no sign of family life, me or the kids. Just himself. He keeps promising over and over again that it only one time sexting and it was cause he was horny and stressed....he met this girl on that secret social media account and they talked for couple weeks I guess and ended up sexting on snapchat. Saved nudes for 5 days. My world has shattered and i can barely look at him.

Im in a whirlwind of mixed emotions. Im so pissed then hurt. Miss him, he was my best friend....my favorite person. Has anybody been through the same and it worked out for you? Can i be happy again with him? Can things work after something like this?