Poly-Mono relationships is not about change, but acceptance.
I tend to agree with several of the responses in this thread. I am in a V with two monogamous women. Both of them are into me and accept that I do commitment and relationships a bit differently than what they are accustom to.
However I was very clear early on that if they do or do not desire to have other lovers that so long as we are loving, communicative, accepting and supportive that anything we wanted for ourselves was completely possible. That like all things good in life, it required a bit of effort to visualize, communicate and accept.
The not so obvious key in this is acceptance. I like to believe that love is really about acceptance. That you accept that the person you love is different than you are and that difference is a part of the person you are in love with, a part of the package you sign up for when loving them.
I am sure that this likely goes without saying for many "old" polys, but to attempt to change a love to suit your needs is not very dissimilar to treating the person as if they were property. Attempting to change or willingly giving up who you are in the name of love will likely end in a trainwreck of a relationship or an unfulfilled life full of regret.
acceptance = love.