Aoi obviously like Minedera. I wonder if Houjou actually likes him, or just likes teasing him. I could definitely see Houjou excusing herself from Aoi and Minedera's relationship if she thinks they are ready to be set free.
The old student council president seems to be possessive of Houjou. I wonder if she has ever given him the Minedera treatment and then cut him off, or if she has just rejected him over and over again.
Houjou doesn't seem like the type of person who would let herself be "tied down" to a relationship.