Dialogue presumes you are open to finding out something new, maybe even that what you once thought was an utter and entire truth is not really all there is to think or say or act on a subject.  If you are not open, then all you can do is repeat, repeat, repeat your own vision of what is the truth - you don't grow.  And, after you have presented your vision of what is truth, you have nothing more to offer except repetition.  You want to teach but you don't want to learn.  

If you cannot make room in your heart and your set of beliefs and faith practice for someone who is gay and wants a life partner, then that is okay.  There are others - parents, siblings, cousins, friends, co-workers, neighbors - who can make room.  What you can do is let them.  You don't want this dialogue about same-sex love but would you let the rest of us who do want it have that conversation?