This is not correct. It would have been a lot easier for me to have persuaded my ex-wife to drop her spousal maintenance claim earlier if it was because she never contributed directly to my career in any meaningful way. Section 25 of the Matrimonial Causes Act 1973 on which decisions about spousal maintenance are based say nothing about contributing to a career.
The law actually treats contributions now and in the future for the welfare of the family including any contribution by looking after the home or caring for the family.
To be a potential candidate for spousal maintenance, you only need to prove there is a gap between your income and your needs. To get spousal maintenance, you need to prove your ex-spouse has the ability to pay to meet those needs. That's it. There's no other hoops or hurdles. If there was, vulnerable people who needed spousal maintenance who had ex-spouses with the ability to pay could be left in severe financial difficulty.
@MrsBertBibby is a family solicitor and I think she will be able to set things straight.
However, what I will add is that it's probably less likely that a spousal maintenance claim would be successful today than 10 or 20 years ago. That is not because of some convoluted series of new hurdles required to be successful in a claim but simply because the way welfare works now it is rarer that spousal maintenance will make much difference. Allow me to demonstrate.
My wife has four main sources of income. Her salary, which is £1,100 a month. She has to earn this since Wright vs Wright in 2015, people who insist on remaining a SAHP don't have a leg to stand on. Not that that was important to us, she wanted to work anyway. Her universal credit, which is £565 a month. Child maintenance which is £660 a month. And finally child benefit which is £220. In total, that's £2,545. Next year, her salary is due to rise to £1,665 because of the job she has trained for and this will drop her UC to £260 which means her new income will be £2,805. She also has potential to increase her earnings a lot more when youngest DC is 11 in 5 years time.
In contrast, my salary provides a net of £4,900 (between £80-90k gross). £600 is an essential cost (the commute) and I also pay her the child maintenance of £660 so my income drops to £3,640 which is about £800 more than her. However, I also took on all the outstanding debt which will cost £350 a month for the next three years. So the difference is only £550 and I have much higher mortgage costs because of the uneven asset split so after that we're about even.
In the past before universal credit - so not that long ago - I might have been ordered to pay £275 spousal maintenance to equalise our incomes, even though it might have been a little unfair as my essential costs were higher. However, if I paid her £275 now she would be no better off. Her £565 UC would just drop to £290. Also, in 2018 Waggott vs Waggott made clear the sharing principle did not apply to future earnings. Spousal maintenance is paid on the basis of need - generously interpreted. From next year onwards such a payment would only make her £30 better off and when she fulfils her true earning potential in 5 years time she'll earn too much to have a reasonable claim (and SM just doesn't tent to last that long these days).
Also, the asset split in my case was so uneven (75/25) that even when the youngest is 18 she'll still be better off than me. That was also considered in negotiation.
This is why SM is rare and becoming rarer. You need to be earning a hell of a lot to be able to pay meaningful amounts of SM that aren't just lost against UC pound for pound. More often than not even if there is a SM claim it is small and can be capitalised for a four - or worst case five - figure sum.