Just to apologise if I came across as generally dismissive regarding the impact of WT teachings on sex, that was not my intent.
I am well aware that during the late 60 and 70s particularly there was much more direct "counsel" published, as per your citations. I know from my childhood that the interference and intervention into the private lives of married couples was far more intrusive and clearly affected many.
It is also true to say that the WTS has not completely retracted or changed teachings on many things published in those days so they still stand. For example, as far as I know, despite some words around the elders not being bedroom police, they have not retracted their view that oral sex is not appropriate as it's a practice common to homosexuals.
I am in my 40s and had conversations with peers about oral sex in the 90s. The overriding opinion was that the WTS literature did essentially ban it but if you did it consensually then who was going to know or really care.
I am sure that the behaviour of young ones in the late 80s and 90s dating was not that far off what was going on in earlier decades with people getting into "heavy petting" etc. without too much conscience. I know ones that would sleep with their BF/GF.
As I qualified, my experience of married ones over the past 20 years is that no one discusses WTS policies when it comes to what goes on in the bedroom and does what they want pretty much. I am not dismissing the problems that still may occur in a marriage and I am sure there are some who are affected by feelings of guilt over what is completely normal behaviour. I am convinced however, that the vast majority of problems in marriages I have seen over the time myself and my peers have been married are predominately down to the wider circumstances around simply being hitched to the wrong person. If the sex is bad then this will be part of the cycle that contributes to the deterioration of the relationship.
I count myself fortunate to have been getting married at a time when the impact of the WTS policing the sexual conduct of couples was declining. I can see from your posts and others, such as Flipper, how much the WTS affected the day to day lives of couples just a few years earlier and how much their ridiculous assertions would affect the mental state of single persons and couples engaging in completely normal, natural behaviour.