Welcome Lonely123:
Communicating with someone with BPD can be challenging. I'm sorry you had an argument today and feel bad about it. The fact that he has a history with suicide attempts, must really make you feel you are walking on egg shells. The thread at the link below should be helpful for you to read:
SUICIDE IDEATION IN OTHERShttps://bpdfamily.com/message_board/index.php?topic=79032.0;allThe only thing you have control over is how you interact with and react to a person with BPD.
It can take some time to feel confident with some of the communication skills, but you will likely find it worth while.
Click on the links below to get to some of the basic communication tools that can be helpful: VALIDATION VALIDATION - DON'T INVALIDATESET WISE MIND AVOIDING CIRCULAR ARGUMENTS Validation can be comforting to a person with BPD (pwBPD). Validation doesn't mean that you agree with them on something. It just means that you acknowledge their feelings. You don't want to validate the invalid. Sometimes, it can just be a matter of not being invalidating.
Give some of the communication skills a try and let us know how it goes.