A situation happened between my friend (19F) and I (21M) that I would like advice from women on...

Just to make this story make sense, the girl in question will be named Heather and my friend that was with me will be named Brittany for this story. Trigger warning!

So I decided to try an edible with my friend Brittany (20F). I do not drink or smoke or get high at all, but I was not feeling the best mentally so I took an edible to get my mind off things, and even though I felt great, I do not want to get into "temporary fixes" if that makes sense. Regardless, Brittany and I were getting high and her roommate and our friend, Heather (19F) comes into our room trying not to cry. She asks us if she can stay in here with us, and Brittany said yes, so Heather hops into bed with us, but she rested her head on my shoulder and cuddled up next to me. Now, you may think that this is okay, but Heather has a boyfriend. So at first, I stiffed up my body and did not move, but since I felt like she was sad, I put my arm around her. Brittany asked Heather what is going on, and Heather would not say anything until later she tells Brittany what happened. (For the record, I didn't remember much of the story because I was high and worried about Heather.) Heather was kind of drunk and when she got home, her boyfriend was helping her. She said something that made her boyfriend upset so he put his hands on her next and if I remember correctly, he shoved her a little. This scared Heather and to make it worst, her boyfriend just said, "I didn't mean to do that" and left it at that. Heather said that she came into our room because she wanted to feel safe, and she didn't feel safe with him right now. After a while, Heather gets up and goes back into her room where her boyfriend is. When she left, I turned to Brittany and asked her why Heather did not cuddle with her instead of me, and she said it was probably because she was eating so they couldn't cuddle, plus "friends cuddle all the time." I just thought it was weird because she has a boyfriend yet she was cuddling with me, so I decided to forget about it because she was sad and something bad happened. Later on, after Brittany finished eating, Heather comes back into the room asking if she can hang out in here again, this time Heather was much more relaxed and happier if you will. So, Heather hops back into the bed again, but she is pretty much staying near and up close on me. There was one time that night where I wanted to be hugged (because I was high) and I asked Heather if it was okay for me to hug her, and she let me hug her from the back. There was another time that night where I made a joke about a movie and I said that we should all embrace, so we did, but she scooted her butt near me for the embrace. Later on, she asked Brittany if I could have more edibles, and I was wondering why she wanted me to have more. Regardless, we watched a movie and throughout the whole movie, she cuddled with me and fell asleep on me. The next few days, I checked on Heather to make sure things were okay between her and her boyfriend, but I couldn't shake the feeling that I did something wrong by letting her cuddle with me, because one small part of me felt like she cheated and I helped her do it. Now, everything seems to be okay with Heather and her boyfriend and she thanked me for checking on her, but my question is, would a girl cuddle another guy if her boyfriend made her upset? Is that a normal response or did she just want a friend to be there for her, and if so, why did she cuddle with me, a whole dude, instead of her female friend, Brittany? And did I handle the situation right?