@SkiptheDog, Well glad you can have a chat here then 😄

It's good that you know your trigger. Our relationship with ourself is the most important one. If we're not valuing ourself, it doesn't feel good, or authentic. Trusting your partner is important, but trusting yourself is life. Maybe it can increase confidence in yourself and acceptance that even if you were alone, you would be awesome. 

How do you build a relationship with yourself? Self-care isn't just doing a facial, painting nails or watching a movie. It's also looking in the mirror and saying "Hey you Gorgeous Human! I trust you, I like you!" Sounds funny, feels weird to do, but it can start to break down the negative projections we unconsciously feed ourselves throughout the day, without realising. 

I would look down, say 'sorry' too often, call myself 'stupid' for little things, like if I messed up directions in traffic, etc. Now I consciously try to practice healthy language to myself, ie "It's ok, I'm just on an adventure!" haha

As @Josie72 mentioned, DBT and other specific forms of therapy have proven to be beneficial to many people who experience BPD symptoms. Have you spoken to your GP about getting a referral for counselling? SANE have a support line you can call on 1800 187 263 and also offer a one-on-one guided service. You can find further info here: Guided service (sane.org) 

What have you done that's nice for yourself?

How long since you have treated yourselves? Is it time for a luxurious bubblebath, silkies, and a date night with the partner to bring back the love-bubble? Would you consider joining a social club and getting some girl-nights/friend outings happening to broaden your social spheres? 

Hope that I'm not over-stepping! 😳 💜 😅