Capital 'S' 'Single' should be defined as a state in which you're not a) still pining for an ex, b) pining for a particular crush, or c) pining for a relationship generally.
Because let me tell you, it feels fantastic. It feels like what human adulthood is actually meant for.
Nature doesn't give a flying fuck whether you're happy, it only cares that you reproduce. That's why it curses you with overwhelming lust, jealousies, you name it.
And that's why you wake up one morning and your life has become nothing other than a series of reactions and obligations - some of which might be irreversible.
That's why you can intellectually know someone isn't worth your time, doesn't respect you, whatever - yet your 'heart' still leaps when they text.
Nature just wants those damn babies.
Next time you break up, I recommend NOT looking to someone else to fill the void AND until you're truly, undeniably, non-negotiably OVER your ex - if only just to experience the feeling of emancipation and freedom for a while.
You can always get back to the drama then if you want. But at least you'll be doing it with your eyes open.