Continuity mistake: In the scene where Summer first goes in Marissa's room, Marissa's hairstyle changes - her hair is in a ponytail for most of the scene but in close-ups she has a visible fringe. (00:07:25)
The Shower - S1-E25
Continuity mistake: Aunt Cindy's arms change position back and forth, between holding her drink with two hands, and holding with one hand and the other on her hip, while talking to Caleb and Julie at The Shower, when Julie is trying to get Cindy to leave them alone.
Continuity mistake: At the start of the episode when Sandy and Kirsten are talking at the kitchen counter, Sandy is drinking juice. After the camera switches to Kirsten and back to Sandy, his glass is fuller than it was before.
Answer: He means that if Alex has to go so far as to forbid Ryan from seeing Marissa in order to maintain her relationship with her, their relationship obviously isn't working.