The Great Song Thesaurus says that "If You Wanna Be Happy" was written in 1963 by Frank J. Guida, Carmela Guida, and Joseph Royster. The Harry Fox Agency Website (hfa.com) confirms the songwriter names and says the song was recorded by Jimmy Soul and by Kid Creole and the Coconuts.
You'd think that would settle it and give a clear attribution for the song, but take a look at this:

UGLY WOMAN
(Rafael De Leon, Southern Music Publishing Company)
Sung by the Duke of Iron.

Now if you want to be happy living a king's life,
Never make a pretty woman your wife,
You want to be happy living a king's life,
Never make a pretty woman your wife,
All you gotta do is just what I say,
Then you will be jolly, happy, and gay
— So from a logical point of view,
You better love a woman uglier than you.

Well, a pretty woman make her husband look small,
And very often cause his downfall,
As soon as she marry, there and then she start,
To do the things that would ache his heart.
And when you think that she's belonging to you,
Boys, she's calling somebody else "doodoo." [darling]
So from a logical point of view,
You better love a woman uglier than you.

But if you make an ugly woman your wife,
You can be sure you'll be happy in all your life,
For she will never do things in a funny way,
To allow the neighbors to have anything to say,
And she wouldn't disregard her husband at all,
By exhibiting herself to Peter and Paul —
So from a logical point of view,
You better love a woman uglier than you.

Now an ugly woman give you your meals in time,
And she always try to make you happy in mind,
At nights when you lay down in your cozy bed,
She will coax, caress you, and scratch your head,
And she'll begin to love you like a little baby,
And call you sweet names like "Sugar Daddy,"
So from a logical point of view,
You better love a woman uglier than you. heh!

from the Alan Lomax Collection CD, Calypso at Midnight! The Live MIDNIGHT SPECIAL Concert, Town Hall, New York City, 1946


The tune isn't the same, but the lyrics sure are similar.
-Joe-