We did it for 14 months and it was really hard. Just sad and tense - we paid off a bunch of debt though and our kid had time to get used to the idea of our split. Now my ex lives about 2 min down the road, which is very close, sometimes too close, but it's nice for the kid and convenient for us as co-parents. I find I still date and socialize out of the area however and I don't feel totally free. I expect he feels the same way but it's a compromise we make for our kid and also we both like this neighbourhood I guess. I don't know how it will go if one or the other of us decides to have a live-in partner, will cross that bridge when we get to it.
If you are going to do it long term, I would suggest having defined spaces - like your own room with a door you can shut, or even better, move into some sort of duplex where you have two separate apartments in the same house. This will only work if you two have a very amicable, low conflict divorce. There's a book about a bunch of couples who came up with creative ways of parenting and not letting the divorce bankrupt them called Reconcilable Differences. I don't know that I could be as cool as some of these folks but - it was nice to read some stories that weren't all about how a marriage went nuclear.