I am so sorry you are here but welcome. Please look overin the Healing Library., There are great resources and Q&A.
My advise is fairly straightforward and typical
1) Full and total transparency
2) IC for you both
3) MC for both
Your H appears to have some deep seated issues that he needs to discover else u risk dealing with this behavior over and over again.
Is he remorseful? This means proactively trying to help you heal. I could be wrong but it seems he is telling you to leave him to create a pity party for himself because he knows u will cave and beg to save the M.
Why do you want to save ur M to a serial cheater?
How did you "get through it" last time?
What sexual problems?
Are u fighting for M because u r afraid to be alone or change?
Will he change? I always thought my ww would have some epiphany moments and come groveling back. I then had lunch with a few other men that went through the same thing (midlife crisis and a cheating spouse) ...unfortunately the old spouse never returned, they were broken beyond repair. (sorry it sucks).