Once you start a relationship, it's all about the fucking. You meet up for drinks, then you head to one of your apartments (or just the back alley if you're revved up enough) for some sex. Pretty soon, you're skipping the drinks and just going over to each others' houses for a booty call. But then something happens. Someone sleeps over. Then there's breakfast. Maybe an afternoon movie where you share some popcorn. Followed by dinner. Pretty soon, the relationship that was all about fucking is suddenly all about eating!
I have a friend who would always balloon up a relationship. The guy would get sick of living with a sloth, so he'd dump with her, she'd go on the break-up diet (pinkberry, red wine and Xanax), and get thin again. He'd see her out somewhere and assume she had gotten "healthy" then get back together again where the whole cycle started all over again! Is being in a relationship really worth not being able to fit into your carefully curated collection of skinny jeans?
As the great Kate Moss once said, "Nothing tastes as good as skinny feels..." Including the dick of a guy you're sucking just so you can call him your boyfriend!