Why is love such a bitter sweet emotion when you eventually find it

I found love late in my life 39 , but truly finding it difficult to deal with the complex mixed emotions , like jealousy and understanding of the level of commitment you expect from another , without smothering them , but the joy of sharing everything and closeness is exhilarating , however far apart you are , not sure if I broke up with them , I could bare to let myself love again