Hi Littlemisslost
I feel you are talking about what has been happening to me - depressed H, studying in your thread, apart from I have no ex to contend with.
I never felt that I could leave even though I have family nearby and he didn't, but I often asked him to go.
In the end he did go.
I'm on the whole doing OK, balancing work, children, housework etc. I too was studying till last year and he left just as I finished my course, maybe that's what he was waiting for - I don't think I could have ever left.
Things are still raw for me, so at the moment I can't say it's been the best thing, but the children seem to be getting on with it better than me and more accepting of the situation, and I feel they are better not seeing all the arguments etc. He went back to his parents which is quite a distance, but he does make the effort to see them alot, however it's helped that he is still working up this way.
I'm afraid I have not got much advice as I'm still going through it, but maybe knowing that someone else understands how you are feeling may help.
I do think though with me things could not have gone on the way they were and something had to happen I was just not brave enough to do it. Perhaps in your situation you have to be that brave person, and as others have said at the moment it could just be a temporary thing, which may soften the blow for DD. Ours was initially temporary, although he too was a man of little words and I wanted to keep the children informed as best I could so I could reasure them about were they would live and who with and what was happening, but felt I couldn't cos I did not know what was happening as he would not talk. If you are the driving force then you can provide that solid rock for your DD.
Not sure if this has helped - good luck.