Is the website data on iPhone the sites you've went on or can it be ads too?

So here's what happened, I went on a site on my boyfriends phone a while back and I couldn't remember the name so I was going through his website data to try and find it when I seen a link for a hook up site. I asked him about it and he said he's never went on it and it's probably just an ad or something but I can't help but no believe him. All I want know if its possible that it was an add?

Who knows, this info means nothing

where are the answers to the questions.