Hi S.! Up until recently, I was faced with the same problem. I have four children, two with my husband & two older kids from earlier on. There was a time during the most intense part of our troubles where I felt just like you - like I needed him there to help me secure an ideal family unit. But I also realized that my goal in raising my children was to raise people that would be more confident & self-aware, learn better people skills & make better relationship choices, & develop positive self-esteem. So, then I decided that my goal for my children & the relationship I have with them is far more important than my marriage because my husband was not fulfilling the positive attributes I needed my children to learn. You said that there is fighting in front of the children, right? Fighting is very intense & gets people's attention whether they like it or not. Your children, all children, learn through observation. I decided to play a more active part in monitoring my own behavior & strengthening the bond with our two youngest daughter's (my boys live with their dad) because I am their first teacher. If they see that I accept the way my husband treats me & continue to allow it, they will allow & accept their partner's to treat them in the same manner, whether they know it or not, because it is an environment they are conditioned to.
"He hasn't earned the right to be your husband or a father. I am sorry you have to go through this. But, keep your head high and smile and give your kids extra love and spend lots of time with them playing games, cards, reading and it will be okay!!!"
As for your relationship with your husband. How he left without saying good-bye & how he has treated you is not acceptable. Stephanie is right here! You have put so much energy into "What-to-do" when really there was nothing that you could have done. Your husband's actions are a sign of someone who lost touch with themself &/or they are not secure with their own self - they may be less emotionally developed.
Whatever his reasoning is, it's okay - that is "his" reasoning. My husband spends a lot of energy focusing our problems onto me. That's is okay, because I know now that I am doing what is important for me to raise my kids the way I want & they will learn what is important. It is important for you to now find where you do have substantial & ultimate influence with yourself & that of raising your kids, and then redirect your energy on developing them - what do you want to teach your kids? what will your time playing together look like? what is the message you want your kids to learn when you discuss the new living arrangement? Your kids are depending on you - make this a positive journey for all of you - it is possible.
Re-discover who you are. Make it a game. For example, when the kids are sleeping, make yourself a first date type dinner & while your eating there with yourself, write down some things about yourself you'd like to know, what do you like to do, where to go... etc. I know this sounds silly, but it's now time for you to take back the energy from your marriage to you & your kids. Re-establishing a connection with your kids is vital & will help you all get through this. And if you make it a fun journey, your kids will remember it!
It is also important when the children ask about their father, to respond with the love you do have in your heart & re-assure them that he loves them, but daddy just needs to rest his head - because the truth is, as parents & busy people, we all need a break. Don't put them in the middle as you set them up to feel like they have to choose! They may get angry & resentful & may say or act out in a way that makes you feel guilty - this will HURT! But these are natural feelings for the kids to experience. If this happens, approach them with understanding, listen first & ask what they think would make it better. Even if their ideas seem outlandish, giggle & be open to the fact they want to be a part of the solution, & they won't feel helpless & develop hopefulness. While feeling the pain yourself, as your kids talk about their's, it's important to remember that you are now their only role model, so here is your opportunity to model stregth & courage & that it is okay to feel hurt & talk about it. it'll get easier as time goes on & you should also monitor the conversations your husband has with the kids, as you now will want to be sure they are not getting to confused. Ask him what he thinks is best to tell the kids, let yourself be open to allow him to best express himself & maintain a relationship with the kids.
I highly recommend the book Re-Directing Children's Behavior, by Katherine Kvols, go to http://www.incaf.com to learn more.
I know this was very long, but I am currently dealing with the same issue. My focus is now on my responsibilities & to manage how I, or even whether I should, react to my husband's behavior. Many of the things I love to do, that make me "me" - those things I can do for myself that no one else can do to make me happy (writing, art, volunteering) - I am doing again. I have realized that whatever the outcome, my goal in life is to have ultimately happy resilient people around me & develop that in my kids. I've given up on the "how" but rather knowing that it is possible & that I can have these things, without a doubt, makes my days much easier.