This mantra, repeated to myself, helps remind me of the acceptance I seek:
"I forgive you for not loving me the way I want to be loved.
I release you to love who and how you want to love."
Obviously, they don't need my permission, but for some reason, I feel better giving it to the other on an unspoken level.
I also check in with myself via journaling, on a regular basis, to make sure I'm not harboring too many negative emotions or unrealistic expectations.
I can choose to accept, change or leave any circumstance. If I don't choose the last two, I must choose the first otherwise I am choosing misery by default.
On a separate note, if you feel this person has narcissistic tendencies, then everything everyone here has said is doubly important.
"It is no measure of health to be well adjusted to a profoundly sick society."