T.G.
There is no timetable for how long a person should grieve. Grieving is a very personal experience and is different for each person. Unfortunately there is a preconceived idea that you should at least wait a year. A lot of people think if you don't, it's too soon. And they think after a year is up, you should be ready to move on (even if you are not). So, be prepared to be judged negatively (possibly by your husband's family) if you start a relationship. My father had this experience when he started dating and married shortly after my mother's death. My mother's family has not spoken to my father or us since. The understanding of your children to grasp this relationship will be dependent on their ages and how they are handling the grieving process.
One last thought. Your husband loved you and would want you to be happy. The memories of your marriage will be with you always.
I wish you the best.