In this denomination's statement of faith, they specifically state this is not acceptable behavior. So I am wondering if the modern day thing is for Church leaders to openly act in defiance of the official position. I have similar issues with the leaders ignoring the stance on alcohol as well.
In my former post I had mentioned something about "the actual doctrinal stance which undergirds [your church leaders'] behavior." A bit vague, but as long as Strivax more or less raises the issue (and reminds me of something in so doing), naturalistic evolution might be an example of what undergirds your church leaders' sexual morals--not that it necessarily does, but the issue raises a convenient possibility for me to explain my phrase ("for the sake of argument") and a certain possible logical flow. And the topic might be one you could broach with your leaders, depending on your discretion.
In Mt. 19, Jesus bases His prohibition of divorce on the creation narrative in Gen. 2, which language suggests Adam and Eve's relationship constituted the paradigm for marriage--"and the two shall be one flesh" (and "leave" and "cleave," etc. from Gen. 2:24 and textual environs). Paul uses the same Gen. 2 language (among other things) to prohibit prostitution in the same chapter of 1 Corinthians I cited earlier on this thread (ch. 6) ... and argues in Rom. 5 & 1 Cor. 15 that death came through Adam, but life through Jesus Christ.
The creation narratives in Genesis form part of the introduction to the five books of Moses, for our purposes here for example suggesting that the God of Abraham was also identified as the God who created all things in the beginning--the God not only of the chosen nation of Israel, that is, but of all nations on earth. "Worthy art thou, O Lord, for thou hast created all things," as John's Apocalypse records (4:11). Sexual and marital morals in the Bible and our obligations to God stem in no small measure from our status as creatures under this Creator.
Do your church leaders then derive their sexual morals and view of marriage from such Scripture tradition, a tradition to which Jesus and the apostle Paul, at least, appear to have subscribed? If your leaders understand humans instead as products of evolution that can be very largely explained in purely naturalistic terms (which may be challenged in other venues than this thread), even if they believe in the presence and in some ways at least the acts of God, they may be inclined (to some degree) to view human behavior with respect to sex and marriage not as morally adhering to or departing from the divine standard (depending on action) but as functional or dysfunctional with respect to the reproduction and survival of the members of the species (depending on actions which may overlap or not with the actions flowing from belief in the Genesis creation case).
And that, I fear, digressed longer than I had hoped by way of explanation of one possibility (I wish the digression to end here). I hope you see how it illustrates what I had in mind even if I did not have evolution specifically in mind when I wrote my previous post.
Unfortunately, the above explanation (or attempt at it) does not address why your church leaders appear to have been unfaithful to their responsibility to uphold the church's statement of faith regarding sexual morals, but of course I don't know their hearts and minds, only that since and because of the fall of Adam, "all have sinned and fall short of the glory of God" (myself included).