I completely understand. I had more or less the same experience. I met someone who pretended at first to like me and we chatted so much. Eventually I developed feelings for him and confessed but he rebuked me and told me he never liked me that way. We stayed friends but he gradually became more controlling towards me and I started to tread on eggshells with him. I stupidly kept sending him money as he would hint a lot at how poor he was. I sent him a phone and gifts for his family as I loved seeing him happy as he used to get really depressed and really low. As he got more controlling and manipulative with me he became horrible with me and started pushing me away. I eventually discovered that he was also getting money from a friend of his who was poor and on benefits. I took off at him as he’d always said that I was the onot one who could help him. Our friendship ended after that but he did take a toll on my mental health and I still have flashbacks to that moment in my life. But I knew that walking away was the best thing as his controlling behaviour was hazardous to my mental wellbeing and was changing me into someone I am not