What should I tell a new therapist to help them accurately diagnose me this time?

I always thought I just had depression. I hadn't ever heard of Borderline until someone online mentioned it to me a couple of years ago. I read the symptoms, and it fits me very well. The only thing is, I don't do any self-harm or cutting, and I don't have the dissociative symptoms. But I do have everything else. The impulsivity. The loving my husband one day, but cheating on him the next. Extreme mood swings, but not really the "type" for Bipolar.

So...I want to make sure I get a correct diagnosis. Whether this is Borderline or something else. What do I need to emphasize from the beginning to help them know how to help me?

Does it ever get better, or will I be like this forever?

Have any of you fixed your messed-up marriages, or does it usually end in divorce?