Search Results: flirting while in a relationship

I've been with my boyfriend for almost 6 years. I was very happy with him, and never looked at other guys while being in a relationship with him. We were even planning to get married in the near future, and we've practically each others only friends.
Now this weekend, a guy out of nowhere came up to me and started talking to me. I talk to many people and I didn't see anything wrong in talking to him. We spent a whole hour talking to each other (mostly he did the talk). The following day he saw me again but didn't talk to me. He had added me on social media and he probably saw the pictures with my boyfriend, so that's why. However, late in the evening he messaged me and we spent 3 hours talking over social media. Unknowingly, and unconsciously, I started liking him a bit as a person. Then the following day he saw me again and this time I was with my boyfriend. I thought he wouldn't talk to me, but later in the day he messaged me again and we talked for a little while. From day 1 he started flirting with me, and I might have flirted back without even knowing, but it's in my character to joke around without meaning anything. However the last time he talked to me things started to get more serious and I asked him if he knew that I have a boyfriend and he said yes, but he likes me. I had to admit that I like him too but I couldn't do this to my boyfriend, and the following day I cut all contact with him.
Then, silly me, decided to tell my boyfriend what was happening and he got frustrated. He told me that he has to think about it, and he hasn't talked to me back for 2 whole days.
I feel like it's my fault, that I might have ruined a lovely relationship with my boyfriend, but I really had no control over my feelings.
Does it count as cheating?
Did I do anything wrong?

P. S. this story happened all in 3 days.