Ex threatens to apply to discharge payments

My partner was awarded a periodical payments order in the sum of £500 per month in 2011. This is during joint lives or until she remarries or until further order.
We have been cohabiting for 6 years but our joint income is only modest as I had to share my pension with my ex wife.
Her ex husband's solicitor is now threatening to apply to discharge the order unless she accepts an offer of £10,000 to take her to state pension age. He and his new wife are still high earners with considerably higher joint income and assets.
My partner cannot afford legal representation and would be content to capitalise but unsure how much is a reasonable amount. Also worried that she could incur his legal costs if she does not agree.
The court order states "...the Respondent shall not be entitled to make any such further application in relation to their marriage under the Matrimonial Causes Act 1973, s23(1)(a) or (b). Should this preclude him from applying to discharge?
Any advice please?

I think your partner probably misunderstood the order. Back in 2011, judges used to award joint lives maintenance fairly frequently. However, they did not do so because the intention was that the maintenance would go on until one of them died. They did so to leave it open ended and to put the onus on the payer to come back and apply to vary at the appropriate time, which the ex has now done. The payer in this case has been incredibly generous at allowing it to go on this long, especially when you have been cohabiting for 6 years already.

13 years of receiving maintenance by someone who even now hasn't reached retirement age would be almost unheard of now, even with young children. With the cohabitation on top going on for 6 years, it is very likely that if this goes to court the payments will cease within the next 6 months. Your partner might even get a telling off for not having sought their financial independence sooner.

I would recommend they take the offer of £10k.

Also, just to explain. That clause prohibits the ex from applying for periodical payments from your partner. It does not prohibit them from applying to vary the periodical payments that they pay.

It is unusual that there wasn’t a clause to end the payments upon cohabitation of six months.

How old is your partner and her ex? Your post suggests that your partner may be 20 months away from state pension age?

If this is correct then what is your partners state pension forecast as it will probably more than cover the loss of the SM payment? If there is a shortfall now is the time to plug the gap by buying extra NI credits. Perhaps it would be possible to negotiate the cost of these into an improved buy out offer.

Thanks for your advice. My partner has now accepted the capitalisation offer.
Regards
Paul