Unfaithful
Infidelity
noun, な adjective, の adjective
ふてい
浮気 （うわき） Cheat, Cheating, Affair
不貞 （ふてい） Unfaithful, Infidelity
不倫 （ふりん） Adultery, Infidelity
An Unfaithful fool ふ takes てい to the brothel.
He claimed only his foot ふてい was Unfaithful.