<human>: Can you condense the text into a few key points?

Throwaway because it's 2014 and everyone in the world uses reddit. 

So my wedding is coming up towards the end of December. My sister, Jessica, is a bridesmaid and her boyfriend, John, is one of my groomsmen. We have a small wedding party, too. They've been together for about 5 years. I like John, but he was a groomsman pretty much on the assumption that he would be part of our family for the rest of forever.

Now, a few weeks out, she's breaking up with him. I don't imagine I will have much of a serious relationship with him now that they're over. I don't know too many details about the situation, but Jess said doesn't ideally want him to be standing up there with all of us. I don't blame her, I mean these will be the photographs and memories we have for the rest of our lives. 

So I guess now I have to "break up" with John as well. I plan on still inviting him to the wedding if he's comfortable being there, just not in the wedding party. Any advice on how to go about doing this? I really don't want this to be like I'm kicking him while he's down., but I can't see any way around it. Any advice on how to ask another buddy of mine to be a groomsman without making it seems like a consolation prize?
<bot>: My sister is breaking up with her boyfriend, who is one of my groomsmen. How do I go about breaking up with him as well?