I know this is all really hard. If you are focusing on your H too much, he thinks you are always going to be there for him and will not realize he can loose you. You have threatened to D, but did not flowed through. I am not saying to follow through with D, but I don't think he is taking you serious. You can do this my focusing on you, GAL, LRT, etc. It does not have to be via D. Plus, if you do decide to D, you need to have worked on yourself so that you are mentally healthy to move on. You also don't want to bring same issues to next R. Regardless of the outcome, you win!!
Exercising has helped me mentally and physically. Even if you start by going for walks a couple of times a day. I do this if I start to get sad or think of H too much.
Do you have Meetup groups in your area or are you in a more rural location? They can be a great way to meet new people.
Regarding snooping, I know this is hard and I have to fight the urge. Did this start back during the first As? Have you stopped this? My DB coach put it a good way. If you snoop and find stuff it will drive you crazy since with DB you are not to focus or discuss A. You will have this new information that will cause you to discuss A which is not helpful or you will have to hold it in which is painful. Your H is going to do what he wants, so it is wasted energy.
Me: 42 H: 40 M: 12 H moved out - 8/2015 I filed - 8/2015