Hey everyone. Sorry in advance my english might be a little rusty. So I (m/26) was in a relationship with my ex (w/24) who got diagnosed with BPD along the way. I loved her unconditionally and she loved me to the moon and back. Someday I looked at her Whatsapp Chats and it turned out her "best friend" wasn't gay. They had an affair for at least 9 months and the whole chat consisted of only her asking him when she could see,fuck or strip for him. But there's more. There were so many fucked up chats with other men/women and as I confronted her she said nothing happened. So even as I confronted her with undeniable truth she managed not being able to tell me the truth and to be honest this is absolutely scary. Long story short out of love I gave her a few chances and she managed to keep lying and being unloyal to me. 

So is this just because she is a bad person, a pathological liar or could it in fact derive from her BPD?