LOl - low-rent rendezvous. But we also have OW co-worker to consider and if she is someone he set his sights on as his new target, he may have decided to step it up to woo her and he may have sprung for someplace like Applebees - lol. A dinner and beverages for two plus tip would be around $40. If he did this 7 nights a week for 5 weeks, that would be $1,400. That's before alcoholic beverages, and any gifts or flowers he might have bought her.
In addition, I'm not familiar with how these meet up apps work (and I never intend to become familiar with them, either!), but is there a fee to join? That would be hard to explain to a wife who was paying the bills and looking at debit and credit card statements, IMO.