Online dating companies are some of google's biggest customers in terms of advertising. He probably viewed something innocuous to do with the middle east and then google makes the leap between that and dating. I've never been on a dating site in my life but I see adverts on bike websites for "cycling dating" because it's clearly an interest they've identified from my browsing history (the cycling that is).
Having said that, I have seen some adverts from google that bear no resemblance to anything I've ever looked at and those adverts work even when you use in private browsing or have a new computer so I'm not sure if it is solely based on your browsing history anyway.