Wittol
Wittol , noun
[Said to be for white tail, and so called in allusion to its white tail; but compare witwal.]
1.
(Zoology) The wheatear. [Provincial English]
2.
A man who knows his wife's infidelity and submits to it; a tame cuckold; -- so called because the cuckoo lays its eggs in the wittol's nest. [Obsolete] — Shakespeare