Many find it much easier to be self-destructive, than constructive for themselves. The reason is, they've been delivering harsh, critical comments to themselves since they were very young, so self-punishing behaviors have become second-nature.
Self-destructiveness can take many forms, and some of them are really subtle. The problem is, no matter how benign they SEEM in the moment to us, they're cumulative. Correcting this bad habit (for that's what it actually is) does not call for you to be rigidly self-disciplined (UGH), or 'perfect.' It merely calls for you to become more CONSCIOUS of the daily choices you make, rather than staying on auto-pilot with the ones that are familiar to you, and therefore, automatic.
Self-constructive choices might look like choosing yogurt for your midnight snack, rather than ice cream. It might mean deep breathing for 2 minutes and self-soothing where you notice emotional pain in your body, rather than running from your feelings and acting-out in ways that undermine you: Compulsively eating when you're not hungry, taking alcohol or drugs to numb your pain, calling up your BPD ex or stalking him or her, stopping your disparaging, critical inner dialogue to yourself in its tracks the instant it starts, gambling, picking at your skin, pulling out your hair, turning to porn or using sex to dissociate from difficult feelings, just to name a few.
If you're self-destructive, you've been recycling this negative behavioral habit since you were very, very young. The disgraceful way you were treated by your parental units instilled in you the belief that you weren't lovable and had no value.
THEY WERE WRONG. You were a perfectly lovable, smart, darling little child, who only needed the love you felt toward your parents reciprocated and consistently returned to you. THIS is essential self-affirming parental behavior to a baby and young child, and most of us missed out on it.
IF you continue to talk to and treat yourself in the ways you were programmed as a child, the dysfunctional people you were (sadly) born to, get to WIN. You can't afford to let that happen!
Each day, we're faced with dozens of little choices. Starting to make healthier, more self-affirming ones is a gradual process, because they're far less comfortable to us, than not changing is. Familiar patterns of behavior are easy to maintain, whether they're good for us or not. Uncharted, unfamiliar new patterns take some time to get used to, before we can feel at ease with them.
The MAIN thing is, if you practice being a bit uncomfortable or awkward every day by making small Self-Constructive choices, and not rigidly holding yourself to doing this "constantly," your mindset will slowly change. You'll start WANTING to make them more often, because they gradually become more comfortable as you begin to reroute neuropathways in your brain that assist in your desire to HELP you, rather than HARM you.
Rome wasn't built in a day, and neither is healthy self-worth, but this is a crucial piece of rebuilding yourself into the kind of person YOU can feel proud of and good about~ and your deeply impaired parental units, BE DAMNED!
Remember, those people set up their lives the way they NEEDED 'em to be (we all do this, incidentally), and now You get to change your self-destructive patterns of behavior, and do the same for YOU, so you can create the kind of existence that feels solid and rewarding to you.