If a man has an extramarital affair he may continue to sleep with his wife whereas if a woman has an extramarital affair she may no longer stay married. There are other differences as well which are generally more severe for the woman than the man.
The laws and their sources related to this idea have been discussed here:
What I want to know is the underlying rationale for these mitzvos that explains why it's more severe for a woman to have an extramarital affair, why she is not allowed to marry more than one man and all the other distinctions between men and women that make the laws more severe for women?
[I have edited the question so that it is no longer a duplicate. Please reopen and remove this sentence.]