Can’t speak for the entirety of the West ofc but here in the UK It’s traditionally the norm that the woman takes the man’s surname; but it’s definitely become less common in the last 50 years or so.

It’s not uncommon to see double-barrelled names; which are both surnames added together (IE: Mr Smith marrying Miss Jones could become the Smith-Jones’) or as you say, retaining their family surname post marriage.

Same sex tend to go down the double barrel or retention routes from what I’ve experienced. I’ve met same sex couples where one elected to take the others name, but I’d be surprised if it was the most popular option in SSM, primarily because of where I believe this tradition stems from.

My theory is that the less theocratical a country is, the less prominent this situation is. Religion eh. Helluva drug.

Not the same in all western countries. Afaik it was tradition in most countries for the wife to take the husband’s surname, except in Italy and Spain. Regular people also often didn’t have surnames, instead they were “son of …”

In the last few decades, most western countries (afaik again) are allowing the woman to chose if see wants to change her surname or not. Or to use both surnames. They also allow the man to change his name to that of his wife. Equality.

And that recent development is also why it’s not a problem for same sex marriage. Back when the wife had to take the husband’s name, same sex marriage wasn’t allowed so there was no naming problem. Countries that allow official same sex marriages are typically also countries that will already have equality for surnames.

It wasn’t the same in all Western countries. For example, it was not a tradition in Portugal for a woman to adopt her husband’s surname, but during Salazar’s dictatorship, the custom was implemented, inspired by other European countries that had this tradition. Here it was customary for people to have the last four surnames of their grandparents, first from the mother’s side, then the father’s.

the west is supposed to be more progressive in most areas

All scepticism of that claim aside, I’m not sure it has something to do with progressiveness, strictly speaking. It’s a historical artifact, to be sure, but as far as I know, the laws and expectations on this have softened somewhat. My wife and I each kept ours, for instance, and nobody bats an eye.

It’s a thing many people do anyway, because sharing a family name makes it more obvious that, well, you’re a family, but even for that, there are alternatives that (in my social environment at least) are just as acceptable. My boss took his wife’s, for instance. Double-names have been common for a long time now (several of my older teachers had them) and German law also allows you to come up with a new family name (even later on, doesn’t have to be right when you get married).

The fact that it tends to be the man’s name in hetero marriages is a relic of a society that thought of marriages as the women coming into the men’s household, long before family names became a thing (as the other reply mentions). Whatever the origin of it, that patriarchal model no longer has any grounding in modern family patterns and no reason to keep existing.

However, a habit doesn’t strictly have to be good or bad. In the case of names, their value depends in what they symbolise. In this case, it used to (and unfortunately in many places still does) represent that power dynamic of the man as head of the household. And it’s that dynamic that would be the target of progressive efforts to break it up.

I won’t say it’s gone entirely, because it isn’t, and there are plenty of places where it hasn’t diminished much, if at all. But in some places, it has softened, and that is reflected in the way we treat family names: You’re no longer required nor strongly expected to use the man’s, and even if you do, that doesn’t mean the woman has to be subordinate.

As a historical relic, the habit isn’t progressive by definition, but if there is neither obligation nor implication of male dominant, it also isn’t anti-progressive. It just is a thing people commonly do (but don’t have to).

Of course, if it were used to selectively disenfranchise some voter demographics, that would give it a new and very much regressive meaning. In that case, the habit would be a bad thing again. I hope it doesn’t come to that.

In the US, it was a tradition. If it was a law at some point I never heard about it so probably way back.

There were always exceptions to that tradition and they are becoming common. Of the same sec marriages I know, they each kept their name.

Of the different sex marriage I know, all but one changed their name but I’m an older generation from many people here. I expect my kids generation to have very different results: we’ll see in a few more years