Friend's girlfriend

One night I was with my friend and his girlfriend at their house. We're all around age 25 and I have known him since childhood and her since they got together like 6 years ago.

We were drinking and taking ecstasy (MDMA pills) which is known to make people very emotional and affectionate. We were all talking about old times and all getting emotional and saying we all love each other and hugging as friends do on ecstasy. She was then sitting next to me and we were kinda cuddling but there was no sexual intent behind it and my friend was there as well and didn't mind. Later on, I was in the living room listening to music and they both disappeared into the bedroom for like 10 minutes but didn't shut the door. I couldn't hear them because I had music on but I knew they were in that room and I decided not to bother them because they were probably having sex so I just sat in the living room. My male friend eventually left the bedroom and went to the bathroom. Then his gf shouted my name and I went and looked in the door and she pretended not to notice me. She was laying on her belly in nothing but a thong and I could see full side boob. I said what, but she kinda pretended not to notice me and I just went back to the living room and my friend stayed in the bathroom for like 10 minutes.

I know she at least wanted me to see her but I kinda suspected that she wanted me to come in while they were fucking or to come in to the room with her after. It kinda seemed like he didnt mind either.

Then the next day she was laughing and saying she hardly remembered a thing.

What would you do in that situation?

And most importantly, IS IT NORMAL?