Games with a primary goal/adventure that do not advertise, but contain, an important romance plot

"Love finds you when you least expect it".

I've come to the feeling that romance isn't always that great of a back-box marketing topic. Dating sims are dime-a-dozen visual novels, often cycling some tiring tropes. Optional romances often treat people and relationships as "features" to be picked up as desired and discarded, rather than a give-and-take relationship too complex for numbers in a simulation.

One unfortunate result of making a thread like this is that by posting suggestions, they all immediately become spoilers. Sometimes, it's not that big of a spoiler, as someone might guess it anyway, or it might not harm the appeal of the game overall - especially if it's built around some generally enjoyable adventure.

So: What adventures have you been on where you were surprised by a romantic subplot, especially ones where it had a surprising effect on the rest of the story?