I would honestly appreciate it if you would specifically point out where I am being spiteful.
OP, your whole attitude towards your step mother is hateful, it's really mean.
*When you have guests, that makes you a Host, a Host's job is to make guests feel as comfortable as possible======================= That's right, and the comfort of my immediate family is more important to me than that of a lady I barely know who my Dad felt obliged to marry so he wouldn't be lonely in his old age.
I have no desire to get to know her, as I'm sure she doesn't me. As I've said times, we don't have a relationship and that suits us fine*
A host should treat all guests with courtesy, not just a select few.
by not inviting your father's wife, you are putting him in a very difficult position, making him very uncomfortable, not just on the day, but long into the future, =======================================I've said I'm not sure if this would even be the case. He might in fact realise the awkwardness of the situation and appreciate it would probably be easier for all parties were she not present. I don't know this though. Say it were just parents and a couple of friends, a wedding party of 8, then would you all understand more why is is difficult to have her there? Well to me that room of 80 is as intimate and close as the 8.
I find that hard to believe that you can't recognise that it is going to be hurtful and upsetting.
You seem to of missed the empathy and good manners lessons in life, don't worry it's not to late to catch up,
Lesson one, treat people how you would like to be treated.
Imagine a few years down the line you marry a man who has children, they exclude you from any gathering, and tell you that their father has only married you so he won't be lonely in old age, just so rude.
my ex's wife comes to all the celebrations of our son's life, she married to son's father, I can't imagine being so childish as to exclude her, just so unnecessary unkind.