I am already sad

My Fletcher is going Jan 30th to be neutered. He is 3 1/2 years old and Ive put it off all this time. He needs to be done but I don't want to do it. All these horror stories I read about anesthesia Im terrified. He is healthy and happy now.
How important is a neuter and do the risks outweigh the positive aspect of having one? Like I said, he is 3.5years old and I love him the way he is. Will his personality change?
I have a fixed male also, he was done at 5 months. He had health issues when he was a baby, minor ones though. He changed, he became more clingy and needy and less social. I don't want my fletch to become this way.