Could be an issue for someone who can't control their impulses and urges - both sexual and money wise.
£30k of pre-planned or secured debt - eg car loans, mortgages etc isn't necessarily a problem, but when £30k of debts comes from constantly overspending against income and built up incrementally on credit cards, then it can be a steep uphill to escape from. It seems he had debt management plans in place which means this had been a problem situation.
There was mention of payday loans in one report - that is a sign of last resort lending which is not healthy and often attract crippling interest rates. The interest alone on £30k of debt could easily be £200-400 per month depending on terms and payday loans can be 150% APR interest.
If somebody has overspent their means by £500 a month for say 5 years to build up £30k debt, then when it comes to crunch and you are on a debt plan, you now lose both your ability to overspend by £500 a month AND need to pay back in this case £235 to debt management plus some to the Nat West / Paypal debts ( approx £4k), say £100, and the interest on those payday loans another £100 a month
The reality is that they will feel like they are now £935 'worse off' per month and have a fixed budget rather than being able to borrow whenever.
That's needs a lot of impulse control to rein the spending in and get out of that predicament, especially considering the cost of using sex workers.
I imagine he wasn't open about his finances to his wife either, otherwise the cash spent on sex workers would have rung alarm bells.