I really think you should still go, but maybe reschedule for a later date. That way you have gotten over the shock a little, and can get away. These first few weeks are going to be terribly busy for you--dealing with arragements, life insurances, pensions, estate.......believe me, I went through it with my mom.....
So, if you can postpone your trip maybe for about a month, I think it would be easier for you. And I say easier meaning by that time you will just want to get away from it all, and it might be a good thing where you can be in a frame of mind to celebrate your husband instead of just mourning him.