Feeling disgusted

Two years ago I made a friend online. He had a heartbreak before we became friends. He was all friendly and used to share his stories. We even met few times and he never tried to even touch me. I started developing feelings for him but I did not want to create any drama in my life so I did not confessed at that time. But one day he told me that he doesn't want to talk to me anymore. I was confused and shattered too as he really became a good friend to me. I tried to ask him what bothered him about me but he was not ready to communicate. So I had to let go of him. After three months, he once again popped up in my whatsapp. He asked me about myself and i became angry and bursted on him through chatting. He said he was sorry he will never do this again. But I was not okay at that time so I told him about my feelings and he said that he also likes me but just as a friend. I told him that I cannot talk to him anymore but he kept chatting and calling me once in a while. I tried to be platonic but my feelings started growing once again and I told him that this not working and he told me that he will also not bother me anymore. But he never stopped. I was fallen in a loop. I finally accepted his friendship but something was not right to me. I fell in love with him. He was always friendly and whenever we met he always maintained a distance to me. He had many friends so why did he need me, I am still not able to decode that as he had some female friends too. Eventually, I became distracted from my studies and tried to ignore him many times but I am a human too so whenever he contacts me I used to lose my control. All this while he was always friendly or I was just delusional. I ignored him again for two days but he kept calling me and texting me so I finally confronted him on call. That day he was drunk so he finally accepted that he likes me and even wants to marry me..lol. It was really unexpected for me but he kept ranting it for two hours and made me feel like....huh. Next day the sun had risen but mine had set already. He regretted whatever he said to me. I bursted on him and called him manipulative on phone and he cut the call. He was angry so I texted him and he once again said that he should not had said anything but he also admitted that it was tend to happen as he kept them inside his heart from many days. He wanted to meet me but I did not feel well or my gut feeling was saying so I told him that we will meet some other day. I guess I had hurted his ego because when I told him again that I wanted to meet him that very day and wanted to see him once, he never came. He said that he would try but I guess he never really tried. I called him again and again that day and even texted him but that night he did not once gave a thought to tell me the reason. Was it all a farce? I have anxiety issues and he knows that too. I was really heartbroken that day so tomorrow morning I blocked him from both whatsapp and call. He called me once when he was blocked and might had messaged me too. I had thought that maybe he would reach out to me through telegram but of course it was all my delusion. After three days I unblocked him and called him and when I talked to him I felt like he was not really bothered that I blocked him. We talked like nothing happened between us. Next day I messaged him (damn these block and unblock games...I am not a good player) and asked him about why did he did all these things and he directly said to me without any sugarcoating that he never wanted to come and whatever he said to me that night and day after that night was not real him. Damn was he a bipolar or what? I told him that he behaved like a bipolar but he he was unbothered once again. I texted him some good words and a good bye and he texted me goodbye too. All this while I felt like a manipulated person. On 31st of Dec, he texted me 'hi' at night. My data was off. On 1st of Jan, I texted him about the text and he told me that he texted to check whether i did block him or not. We wished each other happy new year. Do you guys think it is the ending..no no..not yet. My anxiety got severe and I was not able to control myself. My emotions were flowing like a river through my eyes...lol. I texted him once again to let him know what his actions had done to me. I thought that atleast he will behave like a friend. I told him that I do not deserve him and not enough for him that is why he did all these things. He said that my thoughts are right and her girlfriend is irreplaceable. The worst did not come yet. He said that all this time he was just acting and he is a playboy and he wants only one thing from a girl and if I am also ready for those things then I am allowed to message him. He said that I am a boring person and did not fall in his trap. I was dumbstruck and kind of agreed to him. He blocked me after that...lol. I am feeling dusgusted to myself. There is a Darwin's theory of natural selection which says "Survival of the fittest". My question is what kind of adaptive feature should I inherit which will help me to survive from this kind of people possessing narcissistic personality?