Why Sagittarius is unfaithful?

Sagittarius is a carefree adventurous who considers love as another form of amusement.
Expansive and vital, he likes to enjoy the passion he feels and that he arouses in his partner. Uninhibited -most of the time- for him, it all begins as a game. He needs passion to feel alive.
He has his own moral principles and can be a great liar just to justify a clandestine affair.
He struggles to admit his true feelings.
Tip: Never allow him to get bored.

What is the most unfaithful zodiac sign?