there are several really good books available about co-dependency. you could google them. and there are co-dependency groups in some areas that you might attend for awhile.
do you have a therapist? working with a therapist would definitely help you now...before you hit the ground running, so to speak with the new guy......
maintaining a part of ones self is hard if we tend to be the co-dependent type. when i left my marriage, i had nothing left. he got it all. i went into therapy and read several books and did workbooks (and i'm too senile now to even remember ONE of the authors

) and tried to stay aware daily of co-dependency. there is a small daily meditation book that i read every day...it really help. i'll see if i can find it. i think it is by Melodie Beattie??...
maintaining good boundaries is really important and i certainly understand how hard that can be. it's one of my biggest problems.
keep us updated.....xoxoxo pat