Alamo, I would start slow with boundaries, and work on one thing at a time. Trying to change too much at once will feel forced.
Remember, a boundary is an internal thing you set and only enforce if it is crossed. It should not seem like retaliation, because you enforce your boundaries in a very calm and collected manner, without any kind of anger or spite.
This is where being decisive comes in, you are not a decisive man if the boundaries keep moving. You will not be respected if you set boundaries and then do not enforce them.
Man, just read up on boundary-setting on Livestrong.com. All I have to say at first is: I have a lot of work to do. I'm quite certain I experience all the listed symptoms in some form or another during this separation. Where to start? I think the strongest ones are - in no particular order:
A. Over enmeshement B. Disassociation C. Chip on the shoulder D. Lack of privacy