Old fashioned Spy/Romance Novels

Can anyone recommend some good old fashioned spy/romance books- something like older Joseph Kanon or Robert Littell/Ludlum- not necessarily some of the lighter romance genre spy fiction, but the type of spy books where the two main characters help each other/fall in love, ride into the sunset at the end, even if the rest of the story didn’t necessarily turn out well or the way they wanted…? I fear that was more rambling than I wanted but hopefully what I’m saying makes sense to some of you all out there can help me… thanks in advance if you can! 🤗