The common and very familiar Spanish expression contigo pan y cebolla is used in Spain in a humoristic way to let your significant other know "how deep is your love". The fact that a couple may not have a lot of money is not an obstacle for them to get married and live a happy life as long as they love each other. Bread and onions used to represent two types of food that are available to anyone and people with a certain social and economic status would never indulge in eating them, since they can afford a more varied and healthier diet. The idea of contigo pan y cebolla may be expressed in Eng

To complicate matters
Rizar el rizo

To have a screw loose, off your rocker
Faltar un tornillo

To be mad at someone
Estar mosca

To lose your train of thought
Irse el santo al cielo

To give someone a piece of your mind
Cantar las cuarenta

To get bigheaded
Subirse a la parra

To give/have goosebumps
Ponerse la piel de gallina

To be on the ball
Estar al loro

To be down in the dumps
Caer(se) el alma a los pies

To find out the hard way
Enterarse de lo que vale un peine

To not act your age
A la vejez, viruela

Literally
Al pie de la letra

Wisdom comes with age
Más sabe el diablo por viejo que por diablo