I'd suggest you send her the message that you'd only be interested in spending New Year's eve with her if she was unattached.
I don't really like the idea of giving too much power to the OM and wouldn't even refer directly to him. Maybe something like " New Year's eve could be fun. If you were unattached I'd be interested. I've got a few possible plans in the works, so let me know where you're at. Cheers".
I'm in a somewhat similar place right now so I'm hoping for the best for you. Good luck.
