The expression cambiar de chaqueta or ser un "chaquetero" means to hide one's true beliefs or thoughts for convinience or just to fit in an environment in which a person normally does not belong to.
To be fickle, to flip-flop
Cambiar de chaqueta o ser un "chaquetero"
To complicate matters
Rizar el rizo
To say something without meaning it
Decir algo con la boca pequeña
We both though the other would do it
Los unos por los otros, la casa sin barrer
Easier said than done, actions speak louder than words
Del dicho al hecho, hay un trecho
That's another story
Ser otro cantar
Silence is golden
En boca cerrada no entran moscas
A nonsensical discussion
Diálogo de besugos
To beat around the bush
Irse por los cerros de Úbeda
What's done is done, you only live once
Que me quiten lo bailado
To be on the ball
Estar al loro
All that glitters is not gold
No es oro todo lo que reluce
To find out the hard way
Enterarse de lo que vale un peine
A word is enough for the wise
A buen entendedor, pocas palabras bastan
Literally
Al pie de la letra
Wisdom comes with age
Más sabe el diablo por viejo que por diablo
It doesn't hurt to be polite
Lo cortés no quita lo valiente