Yeah, many people hate deaths in romantic stories (unless say the characters are 100+ years old and have had a long happy life together, with lots of kids and grandkids, etc...) and many fanfic archives will have warning tags like (character death) for that. They'll also put up pairing warnings if it's in a shipper archive and there are other pairings in it.
warnings for explicit sex are in most archives(although those tend to be too limited. I dislike hentai sex, too much like porn- all mechanics none of the romantic feelings- boring and annoying. Where I read any romantic sex scene with excitement. I love those. One thing Spuffy (Spike and Buffy from Buffy the Vampire Slayer) fanfics were great in was really hot love making scenes. Even if the writer was lacking in talent in other parts of storywriting many times those romantic sex scenes were fantastic! It's just spoiled me in my expectations of an NC-17 or M fanfic

I get so disappointed in so much of anime/manga fanfic in the M area. I go in hoping for love making and get hentai. ugh.
That brings up an interesting difference between shoujo and shonen manga. in shoujo manga for middle and high school age you get love making scenes, where in shonen ones for middle and high school you get plenty of naked girls but even kisses between couples are rare. Yet in seinen (mens) manga you get hentai explicit sex. Weird.
Shoujo is so much more natural in the way sexual attraction is depicted- For the young shoujo magazines (target audience 8-13) like Nakayoshi and Ribbon, lots of kisses, but little nudity and no sex (or only very vaguely implied if the characters are late teens, going to get married, and it's the final chapters- ie Kamakaze Kaitou Jeanne). Then in older shoujo magazines (target audience 10-16) characters might even kiss in the first chapter, and it's not atypical for them to become sexually intimate before the middle of the story, or at least have some serious foreplay. Lovemaking is often clearly shown, almost never are the sexual organs even implied but their bodies are shown together, making love, with lots of emphasis on the faces, clasped hands with intertwined fingers are also often depicted in these scenes, and usually they speak to each other during the scenes. Tears of overwhelming joy also often are in there (especially for the girl, sometimes the boy is tearing up too, though, depends on how intense the build up to this moment in the story was)
Dream you dream alone is only a dream, but dream we dream together is reality- Yoko Ono 1971
When you go to war, both sides lose totally- Yoko Ono
Remember, our hearts are one. Even when we are at war with each other, our hearts are always beating in unison- Yoko Ono 2009