Chocolate cake doesn’t only make my life complete but also makes me cry when I think about the calories. 

Can one person really make someone complete? This could contribute to an unhealthy relationship. Wouldn't it be better for two complete people to be in a relationship? "I'm nothing without you" should be "I'm nothing without me" imo.

I am not sure, but I guess your question more about how do people feel. Some people are happy to see their kids when they go to a first class in school, the others enjoy listening birds in the forest. Just life, and even food as rose just has said.

It doesn't mean...it feels :))

I guess a person with good friends and family around is a sign of making an individual more "complete" . There is no perfect paradigm for you to imitate in the real world but you can make your life more integrated by getting alone with people well around us. It is said a woman would become more integrated when she has a child but some others said a child is a trouble to a woman.