After my husband died I was fortunate to have access to our Hospice's bereavement program. Support groups met at the hospital and we new widows shared or experiences and our pain and comforted one another. The groups ran for a year and some of us have remained friends and continue to support one another. If you don't have bereavement support at your hospital, check with local churches, even ones where you don't attend, and ask doctors and funeral directors as they may know of a group. It really does help to find that what you are feeling, even some quite crazy stuff, is perfectly normal and is being experienced by others in the same boat.
Also, try to have the legal stuff covered before the death takes place. I know a woman whose husband never bothered to write a will or put her name on the house deed (it was a second marriage) and she felt like it wasn't polite to ask and now she has been a widow for three years and the estate is still in probate---she has no idea of her financial status and stands to lose assets. While there are still two of you to talk about it, make sure you know what to do about paperwork, money stuff, and legal stuff. Some widows-to-be are afraid they will sound greedy so they avoid such discussions. But it is important to be a competent widow and not some helpless dope, and you will be be dealing with situations that are strange to you. You need information. Give yourself permission to take care of yourself.