Recently I found something on the 'net where a writer was complaining about some writing book or course, that it did not cover the all-important topic of writing sex scenes and sexual tension. Even in 'inspirational' (Christian) romances, this writer opines, one has to be able to write sexual tensions and the scene in which the couple discusses their reasons for not having sex.... (??? Well, this writer does admit she's never read any 'inspirational' romances.)
IMO, this just shows how skewed the world is with its attitudes about sex. They don't seem to remember that the whole purpose of the biological sex drive is to make more people. Sex outside the purpose tends toward becoming dysfunctional to the point of being anti-survival.
Sex, like visiting the bathroom or clipping your toenails, is a part of life. But the idea that you have to write extensively about any one of these things is a novel is just a bit odd.
One reason writers has come to use sex-writing as a crutch in their fiction is because it does, when carried far enough, have a certain shock-value. If you can't keep readers hooked with the quality of your writing, throw some sex at them. They'll look at THAT!
But this approach is a little like dropping your trousers in church. Sure, everybody will be paying attention to you, but you won't be winning anybody's good opinion.
A way to view the sex content of the fiction you read is to mentally 'translate' it from sex scenes to something relating to heroin usage. Is the hero looking to pick up a girl-or-guy at a bar? Translate it to him going to a dealer to buy some heroin. Is the heroine wearing an extremely modest dress? Think of it as her waving her heroin supply at other junkies. That scene where the couple are ripping their clothes off and doing it on top of the washing machine? They're really pulling out their syringes and injecting themselves with the drug.
This mental trick is to help us un-brainwash ourselves from our culture's unhealthy obsession with the sex act, divorced from the realities of its biological purpose, and of its probable consequences when misused (such as AIDS and other STDs, jealous rages and homicides, and so on).
The great novelists of ages past managed to write their novels, including romantic novels, without depicting the sex act or 'sexual tension' (will they or won't they have sex...) A couple of generations or so, nearly all writers were convinced that the struggling young writer who turned to pornography writing ('erotica, erotic/sexy romance) to keep bread on the table, was going to be developing bad habits that could destroy his ability to write good fiction later. Maybe we could learn from that, rather than assuming that the way our generation thinks today is the only way there was, ever?