If your story is not romance but it has a romantic subplot, when is a good point to resolve the romance? Just before the story's climax? Just after? Some other point? Does anyone have an opinion on this?
I'd think about the purpose of the romantic subplot, just like with any other type. Does tying it up before the climax make the climax more powerful? Does doing it afterwards make it more rewarding? If you do it at the midpoint, will having been in a relationship for a while mean that the involved characters approach the climactic event differently? Is it an important and heavily-featured subplot that will seem to have been cut off prematurely if you resolve it early, or a relatively minor one that'd seem odd to include alongside more important events in the climax? You have to think about what will serve your specific plot the best.
At the end. Everybody loves a happy ending where the guy gets the girl or the girl gets the guy. It's the icing on the cake after the main story conflict has been resolved. Of course, you can do it ANY time and make it work. But I think right at the end works best.
It really depends on how you write it, how you've paced the plot and dramatic climaxes, and how long the story is. If it takes too long for the two to hook-up, especially if the reasons that keep them apart seem contrived, The will they won't they -dance can get annoying. If too early, there won't be any tension as to whether things will work out for them or not, and that tension can be pretty delicious. In one of my favorite fantasy trilogies, Joe Abercrombie's The First Law the main romance sub plot was resolved in book 3 -- but not in the end alongside or after the climax. So whatever you choose, has to work for your story. Spoiler In The First Law, the two characters became lovers when about 3/4 of the book 3 was done. Everything seemed to go great, but then he had to become king and couldn't continue seeing her. He was borderline ok marrying a pretty woman who hated him and it was left up in the air whether or not she became romantically involved with one of the semi-villains. Good drama.
It really boils down to what you want this romantic relationship to achieve, I used mine really as a way for my character to have a little light shine in the darkness, and a way of showing that even in your darkest moments, there will be someone who cares...
I agree with @izzybot and @ChaosReigns - it depends on your plot/characters and what the subplot is supposed to achieve in terms of the overall plot. If resolving the romantic subplot somehow gives the protagonist the resources they need to get through the climax of the main plot, then finish the subplot earlier. If the main plot is getting in the way of the romance, then resolve the main plot first. The (presumably happy) resolution of the romantic subplot then fits into the denouement as a reward the protagonist earned by having the mojo to stick out the main plot (in line with @Tenderiser 's suggestion). Or perhaps achieving the main plot somehow scuppers the romantic subplot, so you end up with a bittersweet ending. (In this line, one could argue that the romance becomes the main plot and the main plot becomes the subplot It's just a matter of perspective.)
