Don't know if this really belongs here, but I feel like an asshole and I need some outside opinions. Strap in, this is a long story.

Three years ago, I met a woman online named Amanda. We quickly became close friends, she introduced me to her other friends, and I ended up falling in love with her. She had a boyfriend though, so I never told her and tried to suppress and forget my feelings.

Last December, she said that even though she was in a relationship, she still fell in love with others and wanted to talk to her boyfriend about polyamory. Eventually I plucked up my courage and asked if she loved me. She said she did, so I confessed that I've loved her for awhile.

For the next few months, we flirted like lovers whenever we could. Our schedules changed so we could spend every waking moment with each other. 

When I asked if she wanted to marry me, she said she did. That she would, if there weren't so many barriers for us.

One of those barriers being that I live in Illinois, she lives in Texas. We had been planning for me to come meet her for awhile, but with this new relationship we had, I accelerated our plans.

March 3rd, I got on a plane and went to stay with her for a week, to meet her and all our other friends. Before I left, we agreed to set aside our flirting, since she never asked her boyfriend about entering an open relationship.

The week went amazingly. The greatest week of my life. I was to leave early on the 9th, Saturday morning. On Friday, her and I were alone in her room. We were waiting for our friends to show up so we could go to the mall. 

I started talking about how I've had an amazing time, thank you for letting me stay and being so incredible. She did what she always does when I compliment her, which is deny it and say she's just a normal person, nothing special.

I didn't really think things through. I just thought "show her how amazing she is" and the next thing I knew, I kissed her on the cheek. The shy smile on her face dropped as she got up and left the room. 

She texted me a few minutes later saying she felt violated and disrespected. That I broke her trust. We went through with our plans when our friends arrived, but she barely even looked at me for the rest of the day.

When we all got back late that night, her and her boyfriend talked alone on the porch for over an hour. She came in briefly and told me that they were probably breaking up and I needed to get a Lyft to the airport.

It turns out, she told him everything we had done. That she cheated on him.

When I finally got home, I was told by a mutual friend that Amanda never wanted to speak to me again, and that they agreed with her. I've now been blocked on almost all social media by many of my former friends.

My family and what's left of my friends are trying to convince me that she is the asshole for leading me on and throwing me out. I think they have a heavy bias here, so I want an outside opinion.

So, hey Reddit. Am I the asshole here?