How do I explain this to my son?

My son is 15 years old going into 16 in a few days. He has recently started asking me questions about "what is love?" and "Why do we have to follow rules?". I tried to explain to him that love is a feeling that you care not only for someone else but for yourself and your family members; and that rules are important to have security in our life. He also has confusions about religion, since I am a non-believer we don't go to church. He thinks that if God really exists, etc. etc. I may sound cold, but I think religion just complicates life. Life is already complicated enough to be thinking about how we should follow religion beliefs. I tend to not impose any beliefs in him. I believe when he is old enough he will follow his own beliefs such as religion, and love. Am I a bad parent for teaching him this way. I guide him with advices and lots of care. Right now he has a girlfriend, and he started asking all these questions. I explain to him that in life people have different ways of living it. They believe in different things. There is no right or wrong way to live life as long as it makes you happy. Am I confusing him more, since he started asking all these questions. I mean, I don't want him to not believe in anything, but I want him to be conscious that everyone chooses their own path. I have two more little ones and I don't want them confused later on in life. Is it important to have a religion?