I want to invite my friend to a vacation with my BF
Won't they be a third wheel? Why invite them when you're with your boyfriend?
My boyfriend likes her a lot but I think it's a bad idea because she's lesbian
It might cause problems between you and your boyfriend or you and your friend if you invite her into your relationship. Threesomes rarely work out.
Do you wanna have a threesome with us?
Uh, thanks for asking but no thanks, I'm just concerned for your friend, are you able to give her enough attention when your boyfriend is there? It could really dampen the experience of your trip. So why not plan a separate trip so you and your friend can enjoy alone?