The first step, when you are ready to take it, is to try and do the things you need to do - wash the dishes, take a shower, run errands - without crying the whole time. It's not a great step - it's just the first one. You'll get there. Someday, much further down the line, you'll be able to look back on the time you had together and how much he meant to you without hurting so bad you have to turn away. I promise. But that time will come when you are ready. Don't ever feel like you need to be feeling any certain way at any certain time - this grief is your grief, and it will unfold in its time.
One thought someone shared with me brought me some comfort, so I hope this will do so for you, too. Ultimately, you are very lucky to be grieving so hard, because it meant that you loved very, very deeply while he was here.