LTR of 10 months. Smokeshow, feminine, high-paying job. She has a single friend (both 31 y.o high income females). I am divorced with 2 kids.

She plans on going on a vacation with her friend for NYE. I will have my kids, and have not introduced them to her yet, so am unavailable.

I don't want her to go. Other than demanding she not go, unless that is the best course of action, how should I approach this situation?