I'm looking for advice on how to manage big emotional reactions to things

My partner and I have an open relationship which although I'm actively choosing I'm aware that with my bpd I'm playing life on hard mode.

I am getting a lot better at managing myself day to day and with small "triggers" but when something hits certain insecurities I have an intense physical and emotional reaction - crying to the point of panic attack, feeling physically sick, catastrophising that everything is doomed and he would be better off without me etc etc

It usually passes in a couple of hours but I'm looking for help in how to get out of it quicker, minimise the impact it has on my partner, and whether there is anything he could do to help me (I know it's not on him to help and its my problem, but he wants to)