henetha I think the aftermath of someone's death is for most people a confusing time of conflicting emotions - sorrow, regret, guilt, anger, relief, resentment, etc.
Given the particular situation you describe, I think it is perfectly natural, now that the stress and pressure is at an end, that feelings you were perhaps unconsciously holding at bay are now coming to the surface. There is no need to share those feelings with any of your family if you don't want to, but you have absolutely nothing to feel bad about.
I think you did a wonderful, compassionate thing in caring for someone who, despite you maintaining a fairly amicable relationship throughout the years, had caused you unhappiness in the past. You had no obligation to do so but I think it is a tribute to you that you did, and it must have been a great comfort to your former husband.