SO had sex with a girl / dated her in the past and blatantly told me he did not, found out tonight he did because I found a letter from her in some of his stuff I was organizing for him. (Not snooping; we recently moved.) super pissed, yelled at him. Am I overreacting, is this the BPD? Should I even care about the past? This girl now has a baby and he hasn't even seen her in over a year. I don't know what to do. I feel betrayed 