30 year conventional (Jumbo) loan through Wells Fargo.

Most everything I said/read online had me think that I would have to refinance my house to get my STBX off the mortgage and that assumable mortgages were very rare.

Numerous arm-chair redditor/self-claimed lenders incorrectly have commented (on others' posts) that conventional loans are not assumable or that refinancing is really the only way.

There is no guarantee that your mortgage is assumable, but after calling and speaking with the actual assumption department, it sounds a lot more feasible in divorce than the Internet will have you believe.

You'll still need to qualify for your mortgage after the divorce to account for child and spousal support (I believe I'll be fine), and they estimated around 6k in fees, but that is substantially better than more than doubling my interest rate.

For those (like me) who were losing sleep over this, stop reading reddit and call your lender.