*timidly puts on the 'that guy' hat*
Uhm... Not every culture adheres to the "No sexy with children" societal mores. I would google for some examples, but I am at work atm, and that is bad juju to do. (There are at least 3 that I have heard of, and they tend toward being "primitive", but they do exist. Historically, you have ancient greece, and a few others.)
This is not an endorsement, just a needed rupture of the echo chamber.
One of those countries would be the US, or at least the bible belt. Between 2000 and 2010, at least 250 thousand children were forced to marry in the US.
Cases like Sherry Johnson, from Florida, who in 1971 was not only forced to marry a 9 year older man, when she was 11, but that man was also the one who raped her and got her pregnant, are sadly not a thing of the past.
250 thousand children in the US met a similar fate between 2000 and 2010. Texas scores high, with 40 thousand child marriages occuring there. In Florida, about 16500 children got married. Most of these marriages aren't bewteen two children, but between an underage girl and an adult man.
Although the official minimum age to get married in most states is 18, the law is wide open for exceptions, and exceptions are often made, when parents consent, or a judge gives permission.
The problem is most persistent in orthodox religious communities, like christians, jews, hindus, muslims, and buddhists. In Republican states, there are more child marriages than in democrat states.
It is strange and unsettling to consider that in Afghanistan, the law is much more strict than in the US. The minimum age to get married there is 16, 15 if the father gives permission. But there's no exceptions possible below that age.
In a lot of US states, it is technically possible to get an exception to have a toddler get married to a 40 year old.
In Florida, where Sherry Johnson, now 58, still lives, the people are trying to change that. The state is in the process of making a new law that sets the minimum marriage age to 18, with extremely minimal possibilities for exception. Most of this is thanks to the hard work of child marriage victim Sherry Johnson.
The US ministry of foreign affairs considers child marriage as a breach of human rights, and combats it around the world by financially supporting aid organisations.
Yet, in their own country, there's plenty of conservative politicians that are outspoken about their opinion that a child that gets pregnant has to be forced to marry, because abortion and single motherhood are sinful.
https://www.volkskrant.nl/buitenland/zij-moest-als-11-jarige-trouwen-met-haar-verkrachter-en-ze-is-in-de-vs-niet-de-enige~a4576509/