((brokenandconfuse))) Gently, there is no 'already' here. These guys have a giant black hole to fill so will try desperately ASAP.
It wasn't your job to try 'hard enough' - the fact that you were even considering R rather than throwing that douche to the curb is a bigger gift than he deserves.
He is showing you exactly what you would have been 'trying' for - an unremorseful parasite desperate to find a new host.
You dodged a bullet. I did too. My reticence to R saved me when I was unable to save myself. I also saved myself potentially years of False R by not fighting tooth and nail for him.
Even if you and I had put everything into R it would have ended in the same way - just a few years, a few more DD's and lots of pain in between.
He is showing you that right now. Do not accept his blameshifting.
False R is its own special kind of hell. A few months after S I received a FB PM from a woman who had been randomly contacted by my creepy husband.
20 weeks after S this 40 y/o loser announces he is ready to introduce his 24 y/o office gopher/prior OW (which I didn't know about until that point) to my then 2 and almost 5 year olds as his GF.
I know the pain, friend. I wasn't that upset that he was already trolling for a girlfriend as he had already done that in the M, I was more upset that everything he said in False R and throughout our almost 10 years together was a lie.
Get yourself to an L ASAP. He can file for whatever the hell he wants - doesn't mean he has a shit show of getting it.
Time to shift the focus to the matter at hand - protecting you and your kids.
Try not to focus on him and what he is doing. Focus on YOU, your present, your future.