I'm not going to invite my best friend's boyfriend to my wedding
Why don't you want to invite your best friend's boyfriend to your wedding?
Why should I have to waste my time on him
If you don't want her boyfriend around then it's understandable. It is your wedding and you should be able to choose who you want at it. However, I think you should be aware that your friend might be upset about this.
I don't have to explain myself to you.
You're right, you don't have to explain yourself to me. You don't have to invite anyone to your wedding that you don't want to be there. It might be a good idea to explain your feelings to your friend, though.