The great news here is that it seems you're all in a position to have a mature and pragmatic discussion to figure out what's appropriate for the situation.
To answer the question, it can't be answered as a blanket statement. Let's start by focusing on the property; what kind of place is it? What's private? What's shared? With no context, if we're to assume something like a 2BR apartment, while I'd tend to lean your way, the fact that they're sharing a bedroom (as opposed to having two even if both aren't used) means that they individually get less private space. However, all common areas would logically be used equally. As such, maybe something like 60/40 would be more appropriate, but we also have to consider the size of the bedrooms.
Utilities are where it's a bit more black and white. You all use electric. You all use wifi. You all use water. That should be 2/3.
Starting cheating will all of his friends.
The great news here is that it seems you're all in a position to have a mature and pragmatic discussion to figure out what's appropriate for the situation.
To answer the question, it can't be answered as a blanket statement. Let's start by focusing on the property; what kind of place is it? What's private? What's shared? With no context, if we're to assume something like a 2BR apartment, while I'd tend to lean your way, the fact that they're sharing a bedroom (as opposed to having two even if both aren't used) means that they individually get less private space. However, all common areas would logically be used equally. As such, maybe something like 60/40 would be more appropriate, but we also have to consider the size of the bedrooms.
Utilities are where it's a bit more black and white. You all use electric. You all use wifi. You all use water. That should be 2/3.