Pls be gentle in your answers. need help on how to proceed…

I was looking for a specific email on my husbands phone, not snooping. But I was emails with a coworker of his that was talking about a wedding so i wanted to see who was getting married and I was this.

She asked him about a specific chapel to get married as he knows about it and he answered this to her… that she can marry him instead… i read the other emails, they’re a little flirty but nothing crazy… he did go out for a work dinner one time and didn’t say she was there until I found out

Mind you were married and have a 1yo and im 5 months pregnant… I have had it with him. Its not the first time I find suspicious things. I just don’t know where to go from here. I hate to break up this family because of the kids.