What I want to say to my best friend at my wedding: "Dear best friend, He may be the 'love of my life', but you will always be my soulmate." --- but I would tell you "he may be the love of your life but you're my soulmate"
Its never a problem, unless you are involved with a sociopathic narcissist. In that relationship, giving freely of yourself leaves you empty and wondering how you got so hurt. Give your life freely to those that deserve it, not demand it.