Charity is necessary for authentic love to be lived out. Love is sacrificial, stemming from will, and requiring actions purely for the benefit of another. But it is also stems from feelings and emotions that assist the will to be more readily willing to give to the other, while at the same time gaining benefit for the self.
A sacrifice, by definition, cannot include a personal benefit to self. It is a pure action toward the benefit of another, with nothing in it for yourself, and typically accompanying some kind of suffering (which, by definition, is a negative thing).
Charity is sacrifice. Voluntary sacrifice, to be exact. True charity is selfless, therefore, often painful or difficult, but it is also a deliberate decision. You have a choice and the recipient of the charity is not entitled to your charitable act.
Charity is not a man holding the door open for a woman. That’s just courtesy and gentlemanly behavior, which fosters development of charity. Charity is not taking your sick child to the emergency room at 3:00am. That is sacrificial and does not feel good, for sure, and does come close to charity, but duty requires you to act in this situation. To do it is expected, and to not act is a sin, as well as harmful to the sick child.
Giving a drunk friend the only cash you have to get home for his cab fare to get safely home is charity. Tolerating an irritable boyfriend or girlfriend while on a date without letting it annoy you because of the time you set aside for it and the money you are spending, but rather being sincerely patient and accepting is charity. Giving up your night out with friends, which you were looking forward to, in order to stay home with your spouse who had a bad day and needs comforting, is charity.
Charity does not have to be on a “save the world” scale, as you can see by these examples. In fact, charity is most often in the little things. They are the every day opportunities presented to us by God through the people in our lives. These little acts of charity, done without resentment, develop the habit of sacrificial love which preps the person for larger acts of charity. The action was not required, but knowing it benefits another, you decide to do it. Voluntarily. Without any benefit to yourself.