Well, for me at least, loneliness and a feeling of isolation were motivating factors in deciding to pursue new relationships. But aren't there a lot of single people out there who reach out for monogamous relationships for the exact same reason - that they feel that there is something missing in their life?
I am a very family-oriented person, and last year realized that my little family might not be there forever. That if I wanted to experience love and support and security in the future, I needed to start branching out and building a family of choice for myself.
In what comes to your couple, Cranberry, as long as they know about your situation and the doubts it's been causing, and they still want to proceed, I think something very sweet and beautiful might well be in store for the future!
Me: bi female in my twenties