Some background.

I stayed home the entire week taking care of her grandma because she has some health issues.

My only "escape from reality" and to reduce work and life stress is by going to a co creating art event, where we paint a picture all together. It's quite fun and helps me relax a lot.

It's been a difficult year and going to these events is really a way for me to feel better.

My partner went on a work trip one week ago. I asked her if it was okay for me to go to this art event and she said yes but I'm still unsure. Her grandma was supposed to stay here until Monday, but she got better and wanted to go home. I thought it would be okay because I know my partner would love to be with her grandma alone, and that was one of the reasons why I also decided to go to the art event.

She's coming back tomorrow and I will pick her up at the train station. The event only starts around 3 hours after I pick her up and it's a short thing, at most 2 hours, so I will be back soon afterwards.

AITAH in this situation by leaving my partner alone?