It is good to come online and unload, keep it up.

I have received help from psychiatric hospitals before and I think you will benefit from them. Unfortunately for you, the Corvid19 outbreak will delay any progress with professional help. In the meantime, practice patience and find outlets, such as venting online, to get you through the hard emotions. As demanding as your emotions and issues are, they should always come second to self care. Before you confront someone, make sure your bedroom is clean, make sure you have eaten and drank enough water, spend time only listening to music or nothing at all. You need to learn how to regulate your emotions, and then communicate them in a humble and healthy way.

Your wife is not a professional, do not force her to accept you before you both are educated on what you are going through. She simply cannot be the person you need right now, and threats of self harm, or emotional outbursts, might make her act worse for you.

You don't need to have BPD for the therapies designed for it to help you. Don't let her diagnose you, don't pressure her to understand you right away, if you are in this together you will both get help. And that's all that matters in the end, even if the marriage is a failure, at least you both tried.