Um, hello, this is your fiancé's little sister, and you've known her for a hot second. This is not normal adult behavior.

It is extremely suspicious how fast Wren falls for Spencer and dumps his relationship with Melissa in Season 1. It really makes you wonder, did Wren know about Spencer prior to meeting her?

Perhaps Wren was using Melissa to get to Spencer. Maybe he knew who Spencer was because he had purchased and viewed some videos taken by the mysterious N.A.T. club? Seems like something a creepy older guy who's into younger girls might do...