Actually I used to be in that camp. During a long drawn out discussion on this topic we dissected Lev 15:16-18, the Onan incident and three quarters of the rest of the bible. The interpretation I now hold to is biblically consistent in context and across the entire bible. It is true to the original Hebrew as well as to the spirit of the Word. I have not been able to find any scripture that contradicts it. or any circumstance not covered by other areas of scripture where it doesn't make biblical sense
And I came to this belief kicking and screaming all the way. No amount of prayer or study has been able to change the words that are actually there.
Fascinating.