Is this fair? It's a money one

[Oldladyshoes]

First post but long time lurker.
This is not my problem but a friend of mine who asked if this scenario is fair. I will try to present as neutral as possible.

A and B have been in a relationship for 5 years. Both are mid 50s and divorced. No plans to marry again. Both have young adult children from their marriages who all work and live independently.
A is mortgage free but does not work. Medically retired from public sector job a couple of years ago, receives pension.
B has a mortgage. Semi-retired ie retired from public sector job a few years ago and receives pension but works part-time in a different job (lower salary).
Last year B's house needed some major renovation doing which meant they could not live there while work was being done. As B spent most of their time at A's place anyway it made sense to move in for the couple of months or so that the work would take. All was good in the relationship so next step was to continue living together and B to rent out their property once completed.
A arranged for a co-habitation agreement to be put in place which B was happy to do. Agreement states that everything would be 50/50 eg all bills (food, utilities, living expenses) etc., neither would have a claim on each other's property.
A also asked that B pay 50% of the rental income from B's property to A. This meant that once B's mortgage was paid for the remaining income would go direct to B, e.g say the rent is £1000, mortgage is £500, so remaining £500 went to A. B did query this at the time as it felt unfair but A's argument for it was that B's mortgage is being paid for by someone else and remaining money would be saved for 'their future'. As A had arranged the agreement via their solicitor, the solicitor advised B to have their own solicitor to look at agreement as well but (stupidly) B declined as they were happy enough with it and had other stresses to deal with at the time (no excuse but hindsight is a wonderful thing).
Unfortunately both A and B have had to deal with some significant stresses in recent months (none of which are their fault, just unfortunate life circumstances) which has had an impact on their relationship. It seems likely that the relationship is coming to an end, so B has been reflecting on the financial aspect and wondering if they were taken for a mug with regard to giving A all the rental income. B is not planning to make a big issue of it, nor is it the only reason for the split, but they know they can't really question it or ask for any of it back (their 'future savings' which in reality haven't been saved at all as A likes to spend money). So, I just wondered what MNers thought of this set up - does it sound fair to you?

Totally unfair and she was not very bright to ever agree to it.

Not fair on B.
There are other costs to renting out a house not covered by this scenario, which will see B out of pocket.
Also, B is still covering other areas and has historically helped A out.
I had a similar scenario but without such an agreement and i was A. I was happy with spliting the bills as this already meant I was better off financially. As far as I was concerned it was Bs income and there were other costs, like insurance, agent fees, replacing items, tax, etc that B needed the extra bit for.
Eventually we both sold up and got a place together with a % split based on outlay and future costs.
B definitely needs to review the situation and maybe reconsider future with A.

A has benefitted massively from this with 50% of all bills/costs being paid and £500 a month (hope they declared their extra income?)
The money should have been split 50/50 like everything else and would have then benefitted both more fairly.

Ultimately the arrangement means they both have more money. Really the expense of renting out a property should be taken in to consideration and any work on A house B should not be contributing to. But I think B only doing 50/50 on bills is not enough. Has B nominated their primary residence for capital gains tax reasons. Because they may be setting themselves up for a capital gains tax bill.

A is switched on and B is ridiculous in that they did not get their own legal advice at the time.

A was a cheeky fucker even to ask for the money. As it was being saved for their future B should ask for at least 50% back.

B should also not enter into legal agreements without a lawyer in future.

Imo not at all fair half the bills started being paid that A had paid alone therefore they where already making savings on outgoings.

I think B should get out of this legal aggreement , use some of the rental payments to pay extra on their mortgage at the allowed rate and put the rest into a joint account for extras such as renovation holiday etc.

But B had a property that was gaining in value, and should they live with A rent free?

No - the rent to A was fair - if it was under market (should be no more than 50% of the market)

I dont get this stance, should B be a cunt/cock lodger? live for free?

It sounds like they basically have a property each and 50/50 on where they are living. So 50/50 of the profit sounds fairest.

Even a cursory glance shows this to be unfair to B. After mortgage and landlord expenses paid 50% of profit should’ve went to A at most. B is very foolish to have agreed to this and to have not involved s lawyer. Did the agreement mention anything about the saving of the money for shared future? Bet it didn’t. Could ask for their share but suspect B will be disappointed. Time to move on with lesson learned for B.

But previously B was paying all of their own bills, plus £500 mortgage. The mortgage was covered by the rental income, so what was B doing with the £500 they'd previously spent on the mortgage. Surely they should have been saving that? Then A & B would have similar amounts of savings now. If B had simply upped their spending, that would be stupid.

A was a grabby fucker but B was a thicko who 'let their heart rule their head' or whatever the bullshit term for being a mug is.

this is why B was told to get independent legal advice. B didn’t, now B needs to live with the consequences.