Wren would say that was because Abel wasn't really Cath's boyfriend. It was one of their recurring conversations:
"He's a perfectly good boyfriend," Cath would say.
"He's an end table," Wren would answer.
"He's always there for me."
"...to set magazines on."
"Would you rather I dated someone like Jesse? So we can both stay up crying every weekend?"
"I would rather you dated someone you'd actually like to kiss."
"I've kissed Abel."
"Oh, Cath, stop. You're making my brain throw up."
"We've been dating for three years. He's my boyfriend."
"You have stronger feelings for Baz and Simon."
"Duh, they're Baz and Simon, like that's even fair -- I like Abel. He's steady."
"You just keep describing an end table..."