Hang in there and I am thinking of you.
My suggestions are going to therapy weekly to help you cope, seeing a doctor if you are depressed (or seeing your pdoc for possible tweaking of your meds if you already see a pdoc), and have a competent lawyer. Any family/friends support is helpful, too. If you embrace religion, keep your faith. You will get through this.
Regarding kids, keep the kids out of the drama and don't bad talk to them about your spouse. Children are very resilient. They will adjust just fine if they aren't pulled into the drama. My therapist used to be a court-ordered divorce mediator and told me that for kids being affected...it's not the divorce itself, it's how the divorce is handled. He also said as for the couple, if the marriage is struggling and marital counseling fails ... think hard about staying married. Then make that decision ... stay in or get out. Or if your spouse wants out, then accept the cold hard fact, get a lawyer and get out.
Don't divorce through mediation ... a mediator and just the spouses without legal representation. You want divorce in a courtroom with a divorce lawyer. (I'm a lawyer and even hired my own for my divorce.)
Don't argue over who gets the lamp or the kitchen plates - I skipped that, let him have the stuff. (My ex even kept my wedding dress, lol). Not worth the time, the legal fees, and it's just stuff. Things that you owned prior to the marriage are yours, as are gifts given to you, including wedding/engagement ring.
I recommend that you do NOT drink alcohol to self-medicate, I had a brutal, four and 1/2 year divorce (no separation) and drank alcohol to relieve stress. It ended up making my anxiety worse. Get some exercise ... I wish I'd gone that route. Also, four years is an insanely long time to get divorced...most are over with much quicker. I didn't want to stress you out about that.
Lastly, it WILL get better. It will. And when the divorce is final, it's a big relief. I was in a 20-year marriage and never anticipated divorce. I am happy despite being divorced and going through all that pain. I really am happy.
I hope that helps. I tried to include everything I could think of...lastly, there IS love after marriage. I've been in a loving relationship for six years now to a wonderful man. Take care, you can do this.