Thousands of candles can be lit from a single candle, and the life of the candle will not be shortened. Happiness never decreases by being shared.
Basics about Happiness
What is happiness? Is it just the absence of pain and problems? Is happiness a goal that I can reach and what do I have to do in order to get there? Or is happiness just something that one may experience and in the moment when I start thinking about it then it disappeared already?