It's Valentine's Day, and of course, there's a Doctor Who compilation video for that! That's the thing about Doctor Who – it's a show that can encompass literally everything, all of Space and Time, so it's not hard for the editing wizards on the BBC's YouTube channel to find Doctor Who scenes for every occasion. This time, it's the "best" romantic moments from the show. Your mileage may vary, depending on your opinion of those scenes, of course.
Romance didn't use to be a big thing for Doctor Who. Yes, supporting characters often fell In love in the classic show, but that was usually treated as an afterthought and an excuse to get them off the show when the actresses – for it was usually the female companions more often than the men – decide to leave the show or are let go. It was a rather sexist old trope, apparently from English literature. A heroine leaves the story when she decides to get married. It's oddly Victorian. Susan (Carole Ann Ford), the Doctor's granddaughter was the first to do that. Then there was Jo Grant (Katy Manning), who leaves the 3rd Doctor (Jon Pertwee) for the bit of male fluff she suddenly has googly eyes for. Even fierce warrior Leela (Louise Jameson) suddenly and unceremoniously announces to the 4th Doctor (Tom Baker) that she had fallen in love with a Gallifreyan captain and decides to stay and marry him instead of continuing to travel with the Doctor. Her paramour was such a drippy nonentity that we can't even remember his name here and can't be bothered to look it up.
This video compilation is from the new show that began in 2005, of course. The BBC seems to assume that new and current fans aren't interested in the classic show. Showrunner Russell T. Davies moved the Doctor to the fore as a romantic figure for the first time, though it was often hinted at in the classic era, especially starting with the 3rd Doctor. Davies' strategy was to attract new young female fans rather than 40-year-old male geeks since there was no way the show could survive on the latter audience alone. This was a Doctor who actually falls in love with his companions, and with other people. We're not going to talk about the clips. You can watch it yourself. Treat yourself for Valentine's Day the Doctor Who way.