@TS
Why are you asking other people's opinion about this? It's clear that you want to since you've mentioned that you're more than willing to shoulder the expenses and besides, you've mentioned that you're gonna be asking your own bf for a date. That shouldn't be a problem at all. That is IF he really is YOUR bf to begin with.
We all know our views wouldn't matter anyway, whether we disapprove or not, because in the end it's your choice to make, not ours.