Hello Tired, it's slow around here on weekends so just be patient and more "vet types" will chime in later.
I too have been in a SSM for a long time--13 or so years--once a month with an H that watches porn. He will say it's me, and all I know is that I have done my best to "get to him" but it seems that the stars have to align and jupiter has to be with mars, etc, before we can have sex. He is a perfectionist and is never satisfied with....much of anything anymore!
I did a TON of work and I am totally not sorry--Read Gary Chapman's 5 LL book if you haven't--it's a favorite. I can pick out someone's LLs a mile away now (good to know for friends and relatives, kids, another R in the future, etc).
There are other books that will be suggested--spend some time reading them and getting to know some of the sitch's here.
And then, in my opinion, give your S an ultimatum. If you have kids, some people say to spell it out what will happen when they turn 18 if things do not change.
But do a lot of work first--the last thing you want to do is marry the same "type" because you didn't do the work. It seems a lot of the "too nice types" do get sucked right back into a similar sitch if they don't work on themselves big-time first. If you think this may be you, read "No More Mr. Nice Guy".
The other reason you want to do the work is so you can minimize the guilt--my H thought that I would leave him (because I did spell out what I was going to do if the sitch didn't change) and then I started to lose weight, GAL, etc, and he went and filed in Aug.
The work I did has helped me to stay strong and focused, have very little guilt, and help me detach from my H. I love him, but not "in love" with him. This is really not my personality to be so strong and detached. I give these boards and God all the credit.
I know the pain of living like you are--it's mind numbing. Since filing I have had male attention and validation and while I've not yet explored anything (I will wait until the D is final) I see that all the work I have done on myself has made me confident in having a different outcome in the future. I have something that is so, so precious and that is hope.