Good poinmt, thanks. I know some split couples, but that is purely anecdotal, and I bet statistically you are correct.
I wondered if Trump made this split wider, I think he appeals more to men than women.
I'm trying to find the link. I think it was Reuters that used to have their exit polling online in a searchable format. It was great fir answering questions like these.
My main takeaway was that the gender gap was getting WAY too much discussion relative to its size/impact and the marriage gap was getting way too little.
In every demographic category married people were far more Republican than their single counterparts.
As far as Trump, I think he is much more of a symptom than a cause:
20 years ago and more non-college whites were a solidly Democratic voting bloc. Reagan famously appealed to some, most of the "Reagan Democrats" were non-college whites but Trump (in 2016) took more of them than any prior Republican.
This has been a developing rift in the Democratic coalition for decades. Non-college whites used to be reliable Democrats in large part because a substantial portion of them were in Unions. Union membership has been declining so that is part of it.
A bigger part, I think, is that non-college whites are fairly conservative on social issues pretty much across the board. As the Democratic electorate has become more college educated, and more minority, it has moved left on social issues to an extent such that a lot of those socially conservative non-college whites have become uncomfortable in that camp.
The biggest part, I think, is the immigration issue. President Clinton spoke of border security in several SOTU Addresses and the last pre-Trump Republican President was Amnesty enthuiast George W. Bush so this really wasn't a partisan issue until 2016.
Prior to that, many Democrats favored border security and limited immigration. It wasn't all that long ago that
Bernie Sanders was still capable of acknowledging that open borders are a Koch Brothers proposal.
Back then that was considered a bad thing on the left while Republicans Bush and Boehner were pushing Amnesty.
By 2016 the Democrats were more-or-less fully committed to open borders. It had become something of a litmus test in Democratic Primaries with Clinton staking out a position in opposition to deportation that was tantamount to open borders.
Republicans filled the Immigration restrictionist void mostly due to Dave Brat taking out House Majority Leader Eric Cantor in a 2014 Primary. Previously Republican elected officials had pretty much served their Koch Brother type paymaster's cheap labor interests. The Brat/Cantor election showed that the Republican rank-and-file was NOT willing to go-along with top-down positions.
Trump saw this and rode it all the way to the White House. When the 2016 Primaries started there were something like 20 candidates (both parties combined) and only one of them took the side of the American People on the Immigration issue. It is not coincidental that he became President.