Hypersexuality is very common during hypomania and was originally called nymphomania or satyriasis, which can be very destructive to relationships. With bipolar disorder, hypersexuality is marked by an excessive desire for sex and a lack of satisfaction after the act, leading to increased need for gratification.
While this may sound great, for example, to a man involved with a bipolar woman, hypersexuality will frequently lead to affairs. A man may also hire prostitutes, while a woman with bipolar may engage in random sex with men. Of course this behavior is completely abnormal to the bipolar individual, and a great many marriages have been broken up because of untreated bipolar disorder. This doesn’t just affect “liberals” with loose morals, but very conservative individuals as well.
Hypersexuality is a medical problem and affects bipolars irregardless of one’s moral code. A partner should be on the lookout for the first signs of hypomania and take action to get treatment for their spouse.
If your spouse or partner cheats on you while hypomanic, they are responsible for their actions, but keep in mind that this is a strong impulse and requires a lot of self control.