Is OTHER wrong in the post ? POST : Arnold is a long-time good friend from our hometown.

Five years ago Arnold went out with Lucy. Things got serious and they moved in together. About a year in, things went downhill and they ended their relationship. He was brokenhearted, madly in love with her and though they attempted to stay friends he couldn't stop from falling for her causing them to stray again and again.

&amp;#x200B;

After a few months I met a girl at party, Jackie. We became friends and me, knowing Arnold needed a way out of his blues, hooked them up and Walla! they fell in love! They moved in and he was doing much better and seemed to have put Lucy behind. I was so happy for both of them but especially for Arnold for moving on.

&amp;#x200B;

Lucy (Arnold's ex) and me saw each other on the street randomly, mostly small-talk. I was working part-time job and that called for a lot of late-night drinking, something that as I soon found out Lucy was also into. So we became drinking buddies, we would meet about once or twice a month for a beer and maybe a party, naturally after months we just became friends.

&amp;#x200B;

When Arnold learned Lucy and me were becoming friends, he wasn't thrilled but knew he was deep in another serious relationship and asked me to not shove it in his face, to which I obviously agreed. I never mentioned it to him. Now is about 2 years after their breakup and 1 year after he met his new girlfriend, Jackie.

&amp;#x200B;

Now here's my fuckup - one time Lucy and me were out and extremely drunk and I said something sexual to her, yet she wasn't mad, laughed it off and I apologized quickly, understanding its the alcohol talking. We both went on less than a minute later as if nothing had just happened. Still, with lots of guilt, I wanted to tell Arnold, but since nothing happened I decided to put it behind me.

&amp;#x200B;

Somehow Arnold found out, went ballistic and cut me off completely. I wrote him nothing actually happened, that we were really drunk and I'm extremely sorry I didn't tell him.

&amp;#x200B;

Months later we tried to settle it down where I learnt he wasn't really mad about that incident, he was jealous of me that I can be her friend and he can't (because he's emotionally unstable around her or because Jackie wouldn't allow him to), so I was given an ultimatum - either cut off Lucy completely or he's not my friend anymore (alongside with two other friends of mine). I told him I need to think it through but soon after came to realize it would be a shitty thing for me to do to Lucy to just cut her off because her ex is jealous, it's just not her fault.

&amp;#x200B;

I know IATA for not being honest, but AITA for staying friends with Lucy?

&amp;#x200B;

PS:

1. I would have never hung out with Lucy if Arnold wasn't already deep in another serious relationship.
2. I have a girlfriend and very much not interested in anything to do with Lucy romantically.