Please tell me what the difference between the following sentences is
Tomorrow it will be ten years since we moved in.
Tomorrow it will have been ten years since we moved in.
There is little difference in meaning. There is a slight difference in perspective.
Tomorrow it will be ten years since we were married.
This sentence has a slightly forward-looking perspective, as if I'm thinking about the future with my wife.
Tomorrow it will have been ten years since we were married.
Again, similar meaning, but the use of the perfect has a slightly backward-looking perspective, as if I'm considering all that time we spent together.
Neither is more correct than the other, and neither is in any way negative (unless I say it in a way that seems sarcastic or disparaging). These are just two ways to say the same thing but with a subtle difference in nuance.