Feeling lost

[jessm15]

Well I was just checking my emails and noticed I had one from iTunes for a purchase of $65 for an app called "cougar life" I look it up and it's a dating app. I download it and scroll through a few people and ding ding sing up pops The exs photo. I call and ask him about it and he says that his identity and details must have been stolen. Please.
On a whim I enter his username and the standard password he's user our whole R/s and what do you know, it let me login. About 30 "flirts" he's sent to women in their late 40's. A few messages along the lines of "hey sexy... Hey gorgeous... You have amazing legs"
I felt instantly sick to the stomach. I'm trying to save our family and he's spending hard earned money to "flirt" with people the same age as his parents.
My self esteem is just shot right now.
I just want an end to all this.
Why aren't I enough? Why would he rather be with a stranger then me and his kids!?
Last night was horrible for me and I even dropped my kids off with my parents as I couldn't control my tears and didn't want the kids to see me so upset.
I feel like we have past the point of no return. Can anyone see any hope that there's a way back from this?