I've been married for less than a year, but been with my husband for 5 years as a couple, and known him for 18 years now. (I realize i'm only 24. we met in first grade...) My husband knows about my O/L Master and vice versa.
I cannot honestly say where the future will take my relationship with either men. For now I am living in the moment. My husband takes care of me and loves me. My Master takes care of me and loves me. Both are very important men in my life at this point, they just do different things. Do I wish they were the same? yes. In the long run it will save someone from being hurt. Either way I know I will wind up hurt. I'll lose one or the other. Yet it is a choice i freely make out of need for a part of my life that is not filled.
I believe that we can love more than one person in life. We could even live out our lives happily with one person without ever realizing that there's a "more perfect" person out there, or we may find that we love another person but are already with that "perfect" person.