EVERYBODY thinks they only miss the "good times" when their BPD relationship ends. IT'S NOT TRUE.
The very real fact is, people who get involved with Borderlines are habitual controllers. They'd have to be, in order to become the compulsive fixers and rescuers that they are! They're typically Human Doings, instead of Human Beings, as they're dissociated from their own feelings and needs.
These folks grew up in emotionally stressful and chaotic environments, and developed an addiction of sorts, to adrenaline surges (which coincide with that good ol' "fight or flight" reflex we've heard so much about, but never quite understood).
A relationship with a Borderline is never serene, calm or copasetic for very long. There's ALWAYS struggle and strife when you're involved with someone who has BPD traits, because they fear attachment. Someone with attachment fears experiences anxiety when they start feeling very close to you, and will ALWAYS act-out or conjure up a "deal breaker" to diffuse what feels to them like genuine intimacy.
Once a high-maintenance relationship ends, we don't just miss the GOOD times, we actually miss the BAD ones, too~ because in the ABSENCE of the daily, ongoing "project, purpose, goal, dream or fantasy of "Happily Ever After," we are left with a VOID, that nothing can quite fill.
You might try to fill this void with food and overeating, gym workouts, alcohol consumption, self-help venues, etc., but those are merely distractions from your inner void, and it's best to get solid professional help to shrink that empty place in you that drives all addictions and compulsive behaviors.
If you've ever cared for an aged parent, you understand the type of hyper-vigilance you must maintain for that relationship. Ya gotta check in with em at least once a day, you have to make sure they're taking their meds correctly and EATING, and ya feel an obligation to BE THERE for em, right?? You might even grocery shop for your parent, and pick up their Rx meds.
When that parent dies, we're so used to accommodating the burden of having had to attend to them and care for them, we feel a definite vacuum once they're gone. I literally thought to phone my mom almost daily to check in with her, for weeks after she'd passed.
A conflictual or troubling relationship dynamic is VERY similar in terms of what we experience missing, when they're gone. You've had the same distressing issues cropping up on a regular and routine basis. The fights or squabbles are typically over the same fucking issues, month after month, year after year. And yet, you've hung in there, with the wishful thinking of a 4 year old, that it's all gonna work out between you and him/her, and you'll be sailing off into the sunset together in the not too distant future.
Part of what we mourn in the aftermath of one of these relationships is, The Death of a Fantasy. Sometimes when you've been with someone for several years or more, the breakup signals the end of an ERA, along with a lotta hopes and dreams that included that person!
Mourning and grieving your loss is ESSENTIAL, if you're hoping never to attract a repeat performance of that bad movie again. Think of it this way~ if you don't let yourself fully hurt and mourn, you will sidestep the rich learning and growth that awaits you, and you WILL step in that same hole in the road again and again.
For now, let yourself miss the good times AND the bad, because the bad ones definitely helped you sidestep your core emptiness, which you've been running from lifelong, since you were a toddler.