Why did he even meet up with her on this?
So, she's done playing and now wants to be serious. Hm...
https://www.facebook.com/reel/704298841307221
Because when people play house with each other, they are always curious to see what the other person is up to even if there is no intention to get back with them. It seems both people feel very played. Why wouldn't they? You live with each other doing things like a married couple so you end up fighting like a married couple. Except that since there was never a real commitment it's very easy to walk away. Therefore, you live with each other only to find out the ugly things about each other and now you don't want to marry them. Had you been married to them it's not so easy to just walk away so you're more willing to forgive. Of course, if it gets too bad then you can divorce but then at least both people know that they really tried. When you just live with each other than both people feel very used.
Did that guy need to meet his ex when he was already engaged to a wonderful woman who didn't want to explore singlehood? Of course not. But he wanted to satisfy his curiosity since he felt used by the ex.