Having a baby changes every aspect of a relationship.
You go from living your lives how you wish on your own schedules, to having a tiny person depending on you for absolutely everything.
Spontaneous date nights are long gone and a 'romantic' gesture is now getting up to deal with a 3am missing dummy when it's not his turn.
But one of the areas which changes the most is the work set-up, as one person stays at home and the other returns to work at a full salary.
This change caused more upset than expected for one couple after the man said he wants his pregnant partner to continue paying half of the bills while she's on maternity leave.
The woman doesn't know what to do, and posted on parenting website Mumsnet to ask for advice.
She said: "I have discussed this with my partner and he would like me to continue to contribute half towards the mortgage and bills while on maternity leave.
"To do so I will need to use a redundancy pay out that I was given during the first stages of pregnancy. He earns a very high wage."
Other parents were outraged by his demand.
One wrote: "He is being very unreasonable suggesting you continue 50/50. You have to make allowances and work together as a family, after all, that is what you are now."
An outraged mum said: "No, absolutely not. The ONLY circumstances under which I could see this being ok would be if the woman had a maternity package that paid her the same as she normally earned - and do they even exist?! Keep hold of your savings op. You may find you need them."
One suggested: "No, that’s wrong. You aren’t earning your normal pay because you have had a baby for both of you. Tell him to take paternity and still pay half the bills and mortgage. See how he likes that."
Others were quick to suggest she starts charging him for childcare.
One wrote: "I'm pregnant now and got incensed on your behalf as I read. 'Selfish penny pinching b******' - my husbands words as I told him about it. Charge him by the hour for carrying his baby."
Another said: "Only if you invoice him for all the baby bills and child care. How much is a nanny these days? 24hrs a day? So that's what three nannies? If the all do eight hours a day with no days off, so maybe four nannies. A full time Live out Nanny outside London costs an average of £250 per week plus Tax and NI."