I went on a rant in this response, so I hid it.
Summary
So, my characters are a young man who has suffered abuse, including sexual, and a man who is not out and has never been in a relationship with another man. My MC is also visually-impaired, so touch and physical interaction is important. Their interactions during sex, what is ok, what makes them nervous, what triggers memories (or then later doesn't), how they treat each other, is just as important as any other part of navigating and building their relationship. And the progress they make (forward or backward) includes sexual progress. Since they are not out as a couple, its also a chance to show confidence and a different side of themselves. And I like to think that each scene serves a purpose within the story. In fact, one scene starts with sex, there are specific actions and words, that trigger specific memories, cause panic, and cause a character to make a huge decision that changes the relationship. That single interaction furthers the entire plot, and it wouldn't have happened without the sex. And that sex makes my MC uncomfortable, so it hopefully makes the reader uncomfortable too. There was someone above who said they hated that, because they skip sex scenes, but intimacy between my characters is a tension all the way up until this, and then completely changes after. That's how their relationship works, and it was important to show that. I didn't just throw it in for smut appeal.
Why do I describe it? Personally, I think it's strange to write detailed accounts of every other intimate moment in their relationship - their first kiss, their first I love you, private fights, comforting each other over trauma, learning each other's secrets, crying over each other's hardships, spending alone time as family or intimate moments, counseling sessions, inner monologue - but just fade to black the sex. People have thoughts and emotions during sex too. Things happen during sex. Like I said, I only have 3 scenes in part one and 3 in part two, they aren't long, and if I don't think the actual sex serves a purpose, I stop before it happens or start after it's finished. But we treat sex in novels especially (because of the descriptive nature of narrative) either as erotica for some kinky, voyeuristic pleasure or as some unnecessary fluff that's not important. Sometimes, when you're writing about a relationship, it's important. And if that relationship is very sexual in nature, it's very important. And it's no less voyeuristic than reading the millions of other private moments we make ourselves a part of. Just the act of reading a novel is voyeuristic. We describe visual features, expressions, the way someone thinks, their emotional reactions, the way someone talks, the way someone eats, the way someone laughs and cries, the way people touch each other, how things smell, how things taste. All of that builds a character and is expected and welcome unless those people are naked. To me, it would be weird to show those other moments as they happen but then just have two characters lying in bed saying "Sorry for panicking, thanks for going slow." "Yeah, sure, no problem." It's just that sex is made out to be something extra, or something dirty. If you don't like sex or it makes you uncomfortable, that's fine, don't read it. I get it. It's tagged and should be made clear in the description. Or, skip those scenes and just miss those moments. But dislike, disinterest, or discomfort doesn't make sex unimportant. It just means you personally don't want to read about it for whatever reason, which again is completely fine. I personally don't read many novels with heavily sexual relationships because I prefer family and quiet moments and such. But that's not a judgment, that's just a personal character preference. Sometimes, a novel has both, and when it's done well, it's great to read.