Just throwing in my 2c. This was exactly my situation when I divorced 8 years ago (I put $100K down from sale of property I owned prior to marriage). The differences though were that (a) we divorced when the market was high, and the property then had $300K in equity, (b) we used a mediator not attorneys and (c) my name only was on the mortgage due to spouse’s poor credit history. But technically, previous poster was right, if you comingle funds after marriage, they become joint assets.
Hope this helps, good luck.
Forgot to add that Yes, I did get my $100K back.