What is this relationship?

I am a bit confused and I’d appreciate any insight. I’d like to figure out what’s going on here. I spent most of my adult life in an abusive relationship and it made me very weary and also doubtful of myself. It’s been years that I left that relationship but it obviously left it’s deep marks in me as there was emotional and sexual abuse as well as limiting my freedom and denying me studies and going out on my own. But fast-forward to this day. I have known one guy for over a year now. He became a good friend and his been a listening ear and my biggest “cheerleader”. He noticed my insecurities and is always telling me how well I am doing or encouraging me by saying that there isn’t anything that I can’t accomplish when I set my mind to it. After years of being called useless and no good in anything, this friendship has been very healing to me. I have gained a lot of self confidence over the past year and the inner negative talk that I had before has started to subside. We talk every day. Our mornings begin with messaging each other and wishing each other a good day. During the day he’ll text me telling me about his day or just to ask me how I am doing. And in the evening we wish each other good night. This happens without exception every single day. We live rather far from each other but have met several times. And now... I think I have fallen in love with him. Or I don’t know. It feels safe being with him and I never have to fear for a reaction or anger nor choose my words carefully. The ease I feel with him is just... amazing. But here’s the thing: he has called me family several times and also his little sister. That’s what confuses me. And that’s why I haven’t yet told him about having feelings for him even though I think it’s easy to see how I feel. I am also a bit concerned that if I tell him that I have romantic feelings for him, he might back up and I lose this very special friendship we have. I don’t know why it’s so easy talking with him about anything else but voicing my feelings is like the biggest hurdle ever. People around me think that we have a romantic relationship as we’re so close and they don’t believe it when I tell them that we’re friends. So what is this? I guess the only way to find out is talking with him about this. But I am afraid I will end up losing my best friend 😕.