I've done this. We were together for 20 years. He also did not want to split, so I had to push it through. He cheated several times!
The first thing I did was visit a recommended Solicitor. She asked me what assets and debts we had (just the house, 2 cars, 2 pensions and some shares), and with this info she drew up a suggested Separation Agreement. This got sent to his Solicitor (he didn't have one, but had to appoint one).
There wasn't too much back and forth, and it's not like we had multiple houses or anything out of the ordinary. He had a bigger pension than me, so to even that up, in the deal, I would get more cash from the sale of the marital home.
Our timing was crap, as it was 2008 and the house would not sell! In the end he bought me out and stayed in the house, and I bought a smaller house.
He had to sign over some of his shares to me, so that we walked away with an equal number.
It seems insurmountable, but once you let a Solicitor take the reigns, you don't really need to do much yourself.
The divorce I did on-line. It cost £500. Had our children been over 16 years old, it would have only cost me £99. There was an extra step because of the children - can't quite recall what, but the professionals guide you all the way.
It wasn't a nice time, but you just keep going.
This was all 15 years ago now. I now have a much nicer (and faithful) DH!
So yes, start with a solicitor. Forget the free half hour stuff. You need a proper appointment. If anyone you know has been divorced, ask for recommendations.
Good luck! It's not as hard as you think!