Let him miss you as much as you miss him. When he stops using you, and instead cherishes you, you will know it.
I'm sure it does get lonely. That's what GAL is all about. FInd something that fills you up spiritually, emotionally, intellectually, or physically. You'll feel a lot better. The thing I learned the most was that happiness comes from within. Only YOU can make yourself happy, not some other person.
