I plan to send out wedding invitations soon. I have a few guests who have significant others but are not married or engaged to them. When I send the invitation, do I include the name of the significant other or just address them as "guest?"

My cousin has been cohabitating with his girlfriend, but do I address her by name on the invitation? They are neither married nor engaged, nor are planning on it anytime soon.

I have a cousin who has a pretty serious boyfriend at the moment but is not engaged. Should he be mentioned by name?

I also have a distant relative who has been dating her boyfriend for 12 years. He comes to all family events, they live together but are not engaged or married or plan to anytime soon. Should he be addressed by name given that I'm not inviting him directly but only through my distant relative?