what does this sentence mean?

It means that the person who wrote it doesn't really write coherently...

=
Married couples may show a small degree of politeness to each other but never any overt displays of physical affection as would be the case for an unmarried couple.

thank you for your answer, but what do" it is much" and "physical contacts apart" mean specifically in this sentence?
Does the whole sentence mean that if the couple are civil to each other, this is not bad actually, indicating that you can't expect too much out of a marriage, you should settle for simply being civil to each other?
As for the part involing "Physical contacts apart" ,does it mean apart from pysical contacts, there is very limited emotional intimacy between a couple?
Looking forward to further explanation, thank you

I interpret that as not avoiding body contact when sitting or walking, which strangers would avoid. It might extend perhaps to traditional "arm taking" when walking in older couples but probably not walking "hand in hand".

thank you for your explanation. What does "it is much" mean in this sentence?

It means that it is a lot.

it is muchly amusing ... k group hugs mwah

I think it possible that "physical contacts" in this piece might mean having sex.

It is hard to tell if this is the meaning, so you couldn't translate it as that, but just for your information, it might mean this.

immoderate intimacy is, however, to be encouraged