Need some advice, please

Hi, I’m new here, although I have been reading posts for couple of weeks now.
Also, I’m not a native speaker, so please pardon my English 🙂
Long story short, I’m in NC for two weeks now with my ex best friend, who turned out to be my secret love (and feelings apparently were mutual). I’m engaged, and he is in a long term relationship and has a kid. We didn’t have affair, just two long, revealing conversations after one trip with our other friends, then texting for a month and a half, then I decided I don’t want to be that person, I don’t want affair, secret messages, I don’t want to leave my boyfriend, he doesn’t want to leave his family and NC was only possible solution.
After four days, he’s sending me desperate messages, I’m like – ok, you are in pain, I’m in pain, but just leave me alone, please. He was quiet for two weeks and today he’s liking my photos.
I’m so p*ssed off. I won’t change my mind. I’m not answering. But he was my best friend for like ten years, and I know he is suffering, and also right now it’s hard for me to block him and I’m very much in pain too! I need you advice, since I just want to forget about all of this cr*p, about him, about “love”, about everything. How to care less about somebody who really was big and important part of your life?