I have moved your question to the Askaboutlaw forum as this is really about whether your should pay your wife maintenance or not.
You have already agreed to split the net proceeds of sale of the house.
I am not a lawyer, but my understanding is that you have an obligation to support your spouse, and she has an obligation to support you. If you have an income and she has none, you will be obliged to support her. If she has an adequate income in her own right, you probably would not have such an obligation.
As you are getting on well, you should consider first approaching a mutually acceptable solicitor or mediator who would advise you both and who would come up with a separation agreement which would be fair to both sides.
Assuming you agree, then you should probably both take separate, independent legal advice on whether the agreement is fair or not.
Brendan