The one person I am with forever is Me. My relationship with myself is Eternal, so I choose to be my best friend. I choose to love and accept myself and talk to myself as I would a beloved person in my life. I saturate all the cells in my body with Love, as they become vibrantly healthy. I relate with love to all of life. -Louise Hay
Single people want relationships, settled people wonder if they're missing out on something, traveling types miss stability, stable ones are restless, old friends want new friends, new friends miss old friends... The doubt is natural, and everyone you know -- yes, even that person -- carries it sometimes too. Allow yourself to be peaceful. Allow yourself satisfaction in what you have. If you really don't like it, allow yourself permission to make changes.