(A little backstory)

My fiancé & I got engaged 2 years ago , been together for 7 , we have a 2 year old son and 2 week old twin daughters and I’m a stay at home mom.

I was going thru my fiancé’s phone this morning to cancel our Hulu subscription when I saw that he had downloaded tinder back in July, I downloaded it on my phone and logged onto his account, on his bio he has “not looking for anything serious , just looking for a fun night “ I never would have thought he would do anything like this . At the time he created the profile I was around 3 months pregnant with his twins ! I was bed ridden for a few months because I had hyperemesis ( extreme nausea) so I know we weren’t having sex at the time because I physically couldn’t even get up, I’m in disbelief that he tried to cheat on me and I don’t know how to confront him. Please help