Closing costs for loan assumption?

I got divorced a few years ago and kept the house. I have been paying everything on my own the last 2 years but my ex-husband wants his name off of the loan so he can buy his own home (rightfully so).

I live in Southern California so affording a mortgage and all the expenses on my own is tough but I am managing.

I have begun the loan assumption process and my loan officer sent over the initial disclosures that show closing costs at $10,000. What? Why are there closing costs on a loan assumption and why are they that high? I assumed there would be some fees involved but I can't afford to pay that in closing costs.

Am I screwed? I really don't want to have to sell but I don't have $10k to just fork over.