Muslims see sin as a challenge, except for sex?

Muslims see sin as a challenge, except for sex?

In speaking with Muslims, I have found that they see sin as something to be conquered and they are not shy about taking on the challenge of fighting their desires for sin.
A good trait to my mind.

Except for sexual matters.

With these sins and temptations, Muslims hide their temptation away, with clothing and social separation, and never face and conquer this particular group of sins. An example of this would be weddings where the females are separated from the males.

Know that some are more liberal than others and there is some liberalization but think that this is not the common Muslim.

Why is there a double standard?

Face and conquer, so to speak, other sins, but hide from sexual ones.

Thoughts?

Regards
DL