You weren't suppose to find out like this. I was going to tell you eventually.
Oh, c'mon, Lee. It's not like it's all Elle's fault
You had her lying to me for months!
As he's figuring out what's going on and putting the pieces together, Elle tries to apologize and explain herself.
Lee felt betrayed and asked about how long they've been sneaking out for and how long she's been lying to him. He goes off on Noah, going on about how hypocritical Noah is for telling other guys to stay away from Elle while he has her all to himself.
Lee blames Noah for being the reason why she's lying and sneaking around. He punches his brother then storms off