Is there something specific you will or won't do or is it a frame of mind? Are you NOT going to date (or get laid) for example. Are you NOT going to sue the snot out of H? Are you NOT going to file for D? What will be different about what you do or what you feel you can do if you leave the door open for H as opposed to slaming it shut? Which things do you want or can you live with?
2) What is the difference between being done and no longer doing all the work to save the M and going dark?
The situation seems to call for behaving as though you are done and seeing what happens. As a couple of folks have pointed out, it is what you need to do. Why is there a conflict between that (which is a course of action motivated by trying to fix your R) and just being done (which is a course a course of action motivated by giving up on your R). Seems like either way, you will be doing the same things. SO do them UNLESS there is some line you don't want to cross unless you are done. If so, what is that line? And why don't you want to cross it? Is it the legal machinations? Is it having someone else? What?
3) You are afraid that you won't get over him and when he comes crawling back you'll have to drop all the fun things you can see doing once single because you want him back. If he comes "crawling" back, maybe there is something you can do BESIDES just dropping everything and re-assuming your H/W roles? Seems like not only is there something else you can do, but also it would be the wisest thing to do. Crawling back is step 1. The next few steps are working out what went wrong between you together and figuring out what actions, boundaries, etc. will be required so that your R will work out.
In other words, if he comes back, you have the power (my little power hungry pregnant girl) to dictate terms. What are they going to be? You don't have to say "Oh, Well, ok. Move back in". Think about what needs to happen if that scenario occurs.
Oh, and don't talk to ME about giving up chances to get laid BTW. What's it been - a week?
