<human>: Give me the gist of the text in a nutshell

I live in a 2 bed / 2 bath apartment with a girl I went to undergrad with (moved in together after graduating). Although we get along well, we live very independently.

When we started living together we both agreed that it would be okay to have friends and boyfriends stay for short visits. We never really defined what "short" is.

She's been in a relationship for about 2 years. He lives out of town. I don't know him very well, but he seems like a nice guy. He lives about a 5 hour drive away, and he comes in maybe 1 weekend per month, plus sometimes a bit more when he takes vacation. It's never been more than a week, and we've never had an issue.

He's going to be working in our city for 3 months, starting in February. They're both very excited as they've never lived in the same city. Without asking me, it seems like he'll be staying here for the 3 months.

Although I don't have a problem with the guy, it definitely changes my use of the apartment. It's a 2 bathroom, but there's only 1 shower. We really only have one common room, and a third person means more mess, less space, and such. 

Plus there's the ickiness of being roommate #3 while living with a couple.

I tried bringing it up with my roommate, and should got really offended. I understand; they've been looking forward to him being around for a long time (apparently they've known for a while and she just recently told me). She didn't even want to entertain the notion of paying rent, saying she already pays more (she does pay $100 more, but she has a bigger bedroom and the en suite bathroom). 

Thoughts?
<bot>: She wants her boyfriend to stay for 3 months. Won't even pay extra rent. I don't want him here at all.