Ex slept with someone I don't know what to do

[CosmicG]

No doubt about that. My parents were together all through high school. They split up for five years to see other people, then wound up reuniting and getting married. My mom was actually engaged to someone else when she began talking to my father again, so I came very close to never existing at all. Just goes to show you never truly know how things are going to end up one way or another, but things always work themselves out one in the end.

High school sweethearts definitely exist, just don't feel like it absolutely has to be that way at all costs. If it happens it was meant to. If it isn't meant to be, don't bind yourself to that delusion. Way too many possibilities out there.