I am trying to end a toxic friendship right now, and I would like some advice from you guys if you would be so kind? 
My story: 
A while back I got to know one of my fiancé's friends and we became good friends very quickly. He, my new friend, had some emotional problems and I helped him out by being a good lisstener and supporter. He had very good values and ideals, more simular to mine than my own fiancé has. But my fiancé started to disslike him since they were both feeling down and none of them had it in them to help the other one out at that time, instead they started to feel like the other one was letting them down. 
This friend is very needy and wants constant reasurance to know that he can trust me and that I care "enough" about him to qualify as a friend at all. He put me to a test once, when he whenever I'd come to visit he'd allways bring difficult topics up just as I had to leave - just to see if I would stay or not. I told him multiple times that I really had to go and when he got angrier and angrier I'd run out of his appartment, scared of his agressions towards me. 
He has told me that if I really cared about him I should have stayed even though I had other places where I had to be, and that I was a stupid moron for not understanding that. He has also told me that I am a great dissapointment to him and the list goes on. He cut me real deep, especially since I was only trying to do my best to support him and at the same time support my fiancé in their hardships and even though they weren't friends anymore. 
 
He has appologised for this behaviour on several occations, but he still can't decide if he wants to be my friend or not, probably because of trustissues and the fact that he has romantic feelings for me that my fiancé does not aprove of. 
I want him out of our lifes mostly because it hurts my fiancé that I have a friendship with a man who has hurt us both badly and our relationship. But at the same time my friend tries to stay friends with both me and my fiancé in an on/off sort of manner. 
We're affraid that he would take an official ending of our friendship as a declaration of war considering his short temper and passed behaviour. 
He seemed like such a sweet man in the beginning of our friendship, but now he's managed to go against most of his good values! 
 
Please, any advice would be helpfull!