Why women's sexuality is seen as threat by society/cultures/religion.

You're right. It's historically been framed as a moral threat and is more criticized upon females than males because the world runs on power dynamics.

You decide what is morally wrong or right for you. No one else.

Humans can typically only hold one child at a time and it takes nine months to do so, the cost is quite high for indiscriminate sex practices. Men's role in this dynamic is that of the expendable partner, we're not the resource sink when it comes to who is more important. That's why we historically protected our women and coddled them. A population with many females is good but a population with few females is bad. And this is why there are more women than men but the numbers are still close, we needed more women than men but we also need enough men to defend those women from other men who would plunder them. It's also why monogamy has become the dominant partnering idea. Men worked out that to keep them from constantly warring with each other it would only be allowed that they should take one wife. It was agreed upon then that every man could have any woman he could win over, but only one woman. And this satisfied the most men.

There's this idea that women are the only ones being controlled but that's not the case. They are controlled more is all

The thing is a woman can have a child with somebody else and tell her man its his even if it isn't. And he will raise it as his own. A man can not bring home a baby and claim it's hers .. so their kind of is an evolutionary reason I think

Maybe it's viewed as a "power." Some people are intimidated by that.

Probably because women can use sexuality to have power over men. There was also a big increase in the fear of female sexuality during the feminist movement, which makes sense. If women have sexuality and civil rights, there's no stopping them!

By who?

It is not a threat to me. It's their bodies to do whatever they wish.