Do I have to invite my buddy with his gf to my house?
Why don't you want her to come?
Because she's dumber than him. I definitely don't want her to come to my house or hang out with us.
You don't have to like your friend's partner but you should respect them. Otherwise it could hurt their relationship and lead to them fighting.
You're just thinking about them, not about what I want. They have decided to date each other so I have every right to be selfish.
If you want a boys night it is perfectly acceptable. He might not always have time to see you alone but try to respect that he has his own life to live with her.