Dividing rent while cohabitating?

I’m not one to ask relationship questions on here (or many questions at all, actually) but I could really use some un-biased opinions from smart people who won’t think less of me or my boyfriend because of this situation.

My guy and I have been together for about a year and a half. We’re both adults. We’re finally talking about living together when our separate leases are up. I’ve been wanting this for a while.

I have a full time job in childcare that I’m very devoted to and love, but I don’t make a whole lot of money. I make enough to get by with some extras, but I’m pretty much at pay check to pay check point in my life. I’m also going to grad school with the help of student loans. My boyfriend also works hard and is great at his job and makes around four times the amount I do. He is very generous with me. He almost always pays for dinners, movies, entertainment, etc, and gets me lovely, generous gifts for birthdays and holidays. I try to spoil him back to the best of my ability. Money is pretty much never an issue for us. I appreciate his generosity and express it well (I think), and he does the same for me.

So, here’s the issue. My current apartment costs about half as much as his does. Mine is “charming” (old) and basic, while his is new and has all the amenities. When we live together, we will need a 2 bedroom (or 1 bed with den or something) because he works from home and needs an office. He wants to split the rent 50/50. I think that’s unfair to me for many reasons, including our financial differences and the fact that one bedroom will essentially be his.

Am I selfish? Am I right? We haven’t talked a whole lot about it yet, mainly because I want to make sure I’m not being unreasonable.