I grew up in a conservative, Muslim-majority country and in my 18 years there, I did not meet a single person with multiple wives. I heard of one person though - a man from a village who worked in the city had one wife in each location. I never met this man, but a distant relative knew of him. That's it. Every other person I met was monogamous. I'm not trying to justify something you think is wrong, just giving you a bit of perspective that I hope you'll consider.
So far true for Christianity as well according to my reading and what I have been told. The worship part however I can't relate to.
Even if you restrict yourself to Protestantism in the US, you will have trouble generalizing too much; the doctrine of Sola Scriptura[1] is probably the only other universal there.
With regards to sexuality, there is very broad agreement that extramarital sex is sinful, but not much more agreement beyond that. Most protestants are accepting of contraception within marriage; Roman Catholic doctrine is opposed to any use of contraception (to the point of the official stance being that HIV positive married persons should never have sex rather than use a condom), however somewhere between "more than half" and 90% of western Catholics disagree with this.
James Dobson (A well known Evangelical Protestant psychologist) gets plenty of angry letters any time his stance that masturbation is a normal and healthy part of developing sexuality comes up.
(based on my experience in the US; may not be true of Europe)