It still sounds like you have some setting or some particular scenario that is causing you to die from just having sex. If you have 'full grit' (10 fist icons in the top left) and you are trying to have sex with something like a werewolf or werebear, that does sound like a bug.
Can you give a better description of what you were doing or what was going on when you started dying every time you try to have sex with something? How many Grit icons do you have, what monster were you trying to have sex with, were you enticing it with masturbating or were you letting it beat you up, were you in a dungeon, was it a monster out roaming the plains.
The reason people are asking you the questions we are asking, is that we have been playing the game as well and have not encountered a situation where you just magically die after having sex with a single monster, especially if one has enough Grit points.
Believe me, if my character was just dying left and right after being fucked by 1 monster, I would have already posted here about ' bugged game, I die all the time from sex'.
I have run my character all over the island, banging various monsters and never died from sex, unless I didn't have defeat sex enabled or I didn't have enough grit points to have sex with something and not die. As Candy said, if you are defeated and something fucks you, then another monster has sex with you right after that, you will die. I had that happen once or twice to me when I was still learning the game.
The other reason people have been talking about Grit points is because of the in-game description of Grit:
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It doesn't say anything about it being the number of times you can have sex, it is a meter that determines if you die from sex. If your grit points do not equal or exceed the number of skulls a monster has you die.