You should have expected this, you should have really have. If it wasn't obvious with the way he doesn't notice you as much as before, and how he always try to avoid all your intimate touches, you don't know what is.

Seeing him with another girl hurts, right after you arrive home. You can see them doing it very loudly without a care in the world! And you took that as an initiative to break up.

You thought you had move on, but you clearly didn't when he messaged you 'hey' right now.