It lasted for four months, but he was my friend for two years. I can't stop thinking that I was being constantly manipulated by him, even though he completely denies it.
He had a girlfriend when I met him, but he would constantly call me and suggest that we should try phone sex. I reminded him that he had a girlfriend, but he didn't cared that much. I must admit, that I was young, stupid, and I liked the attention. Funny enough, I was also trying to move on from another really toxic relationship, so I thought that accepting his advances might turn out ok for my self esteem.
He kissed me, touched me and tried to have sex with me multiple times, even though he had a girlfriend. He fought constantly with her, and as a result, he called me late at night, looking for a fight.
I never paid too much attention to him when that happened, since in a way, I thought that the verbal abuse didn't matter that much, since at the end of the day, Im important to him, right?
Besides, he would constantly talk about suicide and overdosing, so I was obviously, really concerned about his well being. 
To this moment, I have no idea what attracted me to him. But I did liked the attention, and that he thought i was interesting. I thought that no one else would understand me like he would. I even lend him my DSLR camera (I got it back :p), some books, my Netflix acc, and taught him storytelling techniques. 

Then, we started dating. The first month was ok, even though I'm sure that he brought up attention to him by making constant comments about suicide, and that it totally wouldnt hurt me if he kills himself. So, as a response, I told him that if he dies, I will do it too. I was being totally serious about it, I couldnt see myself without him, but I also think that I might probably blame myself for not being able to help him.

Then, he got more dependant, he would tell me that he was falling apart, that he was going to kill himself soon, so I thought I couldnt leave his side. But I was feeling really, really worn out, I wanted to explore my sexuality and deal with other stuff in my life, and I also felt I had the responsibility to keep him in a good mood. I thought I wasnt being fair with him by being dishonest in what I felt, so I tried to end things wirh him.

He screamed at me like a maniac over the phone, told me that I was a disgusting bitch, and that I lost the most important person in my life, that no one else will love me like he does because of my BPD.
He tried to cover this outburst, pretending that he had DID, and that I had to help him to recover. And he made it clear that I caused it (Which wasnt true).
The fight lasted for a week, and when he told me that he will never see me again unless i kept dating him, I complied. 
 I really, really tried to be on his good side, since I didn't wanted to be abandoned. My therapist told me to take a break from him for two weeks, so I did.
I admit I had a hard time without talking to him, and when the break ended, he told me I hurted him for going away, and even though I was really mad, I forgave him.

Then, two months later, I saw a post from another girl where she was calling him abusive. I didn't believed her at first, but then it clicked: If he did this to me and I made a post recalling the events, I dont think people would believe me either.

I do believe that people learn, so I gave him a chance, I tried to talk things out, set boundaries, and have time for myself, but he didn't respected that. He stayed at my house twice, even when I told him I didn't wanted him to do that.
Two weeks ago, a friend of mine organized a barbecue, which was fun and had a lot of time to catch up with other close friends. I went home, watched a movie, and responded to his messages every 30mins / 1hr. As a result, he sent me a long text calling me cold and abusive. I got incredibly mad at him, and after 20 missed calls, I picked one up, and told him that I wont put up with that any longer, that I was incredibly mad and couldnt believe that I cant be away from my phone, or he would have an outburst like that.

I met his sister some weeks prior. She is a psychiatrist, and told me that he does not show signs of being in inminent danger, that yes, he had a lot of problems, but he isnt in danger.

With this in mind, i thought it was safe for me to show this type of emotion, I hoped that I wasnt being cruel or demeaning, which I tend to be when Im angry. So I told him I didnt want to discuss any further, and went to sleep.
Next day, he calls me and tells me that he's outside my house. And that was like... the final straw for me. So I ended the relationship, the best way I could. He cried a lot, but I tried to tell him that I appreciated him a lot. But we needed to work on ourselves first.

I know that the relationship was harmful, toxic even, but I can't help to empathize with him. Since I'm aware of how hard it is to grow, and understand that you're not in survival mode anymore.
He is really mad at me right now, and thinks that I "betrayed" him, (somehow?)
I just feel really dissapointed. I dont know if I feel hurt, or what even is this texpost, but one thing is fof sure; I dont hate him. Im just hoping that he learns :(