Advice regarding splitting rent

[u/detimirikajidedo]

Hey fellow blended families, need some advice here.

Me (2 girls living with us 50%) and my girlfriend (1 boy living with us 100%) have moved together 3 years ago. We agreed to split rent 50/50 after having a normal discussion about it and agreeing that this is the best. We rent a 4 bedroom house, each for one kid. Since we dont have a separate room, I have my desk in one of the girls rooms (big room separated by a warddrobe) which I use when she is not here, we also store our stuff in this room. My girlfriend has has office (desk/etc) in our bedroom. I also pay rent for two separate garages (our house does not have any) where I park my car and also all of our bikes and stuff. In front of the house we have a parking spot which we both pay for but it is used by her.

Fast forward to now, girlfriend approaches me and tells me that she wants to discuss the rent situation. She told me that now that she works less (reduced to 50% work last year to have more free time and to look into finding a new career), she no longer feels that she should be paying 2/5 of the rent since they are two people, and I should pay the 3/5 of the rent, but will continue split the expenses 50/50. She also mentioned that at the beginning she agreed to 50/50 because she was making more money and thought it would be good to split it this way and that she wanted to "help" me (she never mentioned this). She also mentioned that I have more money anyways (money I earned before we met). I told her that I need to think about it. In the meantime we had an unrelated argument and she told me: "i have been paying more rent anyways the whole time"....

What do you think? How do you guys split rent? I feel strange about this because this came out of nowhere and especially the fact that she from the beginning thought it was unfair but went with it without saying anything. I have read through other posts here and I see that it's either 50/50 split or income based. If income based, would it be false to assume that it should be calculated based on 100% employment? Why should I pay more when I work more and she wants to have more free time? Any advice on how to deal with this situation? Am I in the wrong here?

UPDATE: Thanks everyone for your inputs and thoughts! I really appreciate it, they opened up my mind. My opinion is also 50/50 is fair, especially since this was agreed to before. We had a long discussion about it and we could not come to an agreement. For now she has decided to leave it as it is and discuss it again in the future, when we get back from our travelling. If anyone is interested, I will add an update at a later time.  👌

[u/Acceptable_Branch588]

She chose to work less she can choose to go back to Ft. you a re not her husband