What is the ruling on swallowing saliva while fasting in Ramadan, and does the ruling differ if the saliva is from someone else, such as a wife's saliva?

Swallowing one's own ordinary saliva does not break the fast, because it is difficult to avoid. A fasting person is not required to dry their mouth after rinsing it. However, swallowing someone else's saliva does break the fast, and swallowing one's wife's saliva also breaks the fast. Some jurists feared the invalidation of the fast due to ejaculation resulting from kissing one's wife and sucking her tongue. But if no saliva is swallowed, the fast is not invalidated.