Right. OP. You need a reality check. Because you're getting some terrible advice from "women scorned" and it's going to 1) bite you on the ass, 2) achieve sod all, and 3) is largely incorrect with all the "it's fraud" nonsense.
Paying for non business expenses through the business, is only a matter for HMRC if his accountant declares them as legitimate taxable costs in the statutory accounts and corporation tax return.
If I have a limited company, and use the work credit card to buy £10k of designer shoes, as long as this is recorded as Director's Loan Account when the financial statements are submitted, that's perfectly fine. If he's spent £10k on escorts, as long as the accountant isn't putting that £10k under the guise of "motor expenses" and claiming tax relief, then you've got bugger all to report to HMRC.
I get that you're pissed. And if you told everyone it's over because he's been shagging escorts, that's your call. It matters not one bit which card he paid for it on though. Trying to drag his business down just means less of a divorce settlement for you. See the bigger picture.
I mean, you've phoned the escort??? What exactly is your big master plan with this? Who's going to be affected by the "big reveal" of a recorded message? You'll embarrass yourself looking like the type of person who's hellbent on revenge at any cost. He's a cheat. People will know that by you saying, "he cheated on me." Have some dignity and be smarter than to look like the obsessed ex-wife throughout the divorce proceedings.
The woman scorned look is not a good one. Honestly, harsh as it sounds, no one will care. Your best friend and your mum will etc, but everyone else that you think will be shocked and outraged on your behalf, will make sympathetic noises, then avoid you and having to listen to your drama/dirty laundry like the plague.