Putting energy in others may feel as a sacrifice because we won't get inmediate return.
But should we expect something back? Of course not!
According to my (rich!) experience one always gets largely
compensated in life.
It's like a boomerang: what you give, you get back double.
This is what Alain de Botton says:
"We’re hardwired to seek our own advantage but also have a miraculous ability, very occasionally, to forego our own satisfactions in the name of someone or something else. We won’t ever manage to raise a family, love someone else or save the planet if we don’t keep up with the art of sacrifice."