When you call for dialogue what is there to discuss? The whole question of Judeo-Christian, sexual morality has been settled long before the Incarnation. Fr Martin's book is nothing but a surreptitious call to unsettle the issue, to change the teaching.
The Decalogue is a summary of the Moral Law in the OT and the 6th Commandment prohibits all sexual activity outside of wedlock. Any attempt to relax Catholic moral teaching would destroy the whole of the teaching. That would result in sexual anarchy where anything goes.
If it is going to be possible to abolish the 6th Commandment then all the other Commandments are at risk.