I don't think I can do it...?

My husband and I have just separated only 3 days ago for a history of reasons, mainly cause he is a very selfish man that has treated me poorly for quite sometime, he has never hit me nor cheated (i think) but just speaks to me rudely all the time, I have felt like he has never paid me enough attention and and it has got to a point where we have broken up so many times it has become a joke. Only the other day I asked him to leave and rashly said that it was over in anger, and now he has come back and said he agrees and has ended it. Hearing that from him today has really ripped out my heart and I am wishing I had never said it was over, I still want to work things out as I have also contributed by being insecure and I have some trust issues, but more so I think I have been sufferring from post natal depression as well. The hardest thing is my two kids both young and one still a baby. I am so upset as I write and I know its only new but I dont know if I can deal with this emotionally, how do I keep my emotions to myself and not let me babies become affected by me slowly spiralling out of control? I dont think I can be this strong and I am worried I will not cope, what am i going to do, I am hiding in the study from my son balling my eyes out while he is watching tv and the baby is asleep and I dont know how to stop crying or be strong or just even cope, my whole world has just fallen apart in a matter of minutes and I am so scared....