* un-: This is a prefix meaning "not." It's a morpheme.
* faith: This is the root word, meaning "trust" or "belief." It's a morpheme.
* -ful: This is a suffix meaning "full of" or "characterized by." It's a morpheme.
* -ness: This is a suffix meaning "state of being." It's a morpheme.
Therefore, "unfaithfulness" has four morphemes.