Hmmm... If you and Chops lived together monogamously, I am sure there would be times he would need to be away from you, like visiting family on his own or some kind of business-oriented trip. If that were the case, it would be very unlikely that your thoughts would center on how little time you'd be getting with him. Sure, you might miss him, but you probably wouldn't feel so deprived.
Even though he does spend a fair amount of time away from you, and you can be in touch with him when he's with Xena (he's not completely out of reach), it seems there is something that really bothers you when you know it's "supposed to be" time with you and that doesn't happen, or is shortened. This is a recurring theme for you - I wonder why this issue of how he spends time always gets you so stirred up. I mean, I know you've said your primary love language is Quality Time, but could it also be that you compare how much time Xena gets and want to keep things divvied up equally or you feel like she "wins?" If he takes time normally scheduled for you and spends it elsewhere, does that get made up somehow, like starting the two days over the next day instead of counting it as a loss?
Maybe you guys do need to rethink how he splits his time. Maybe he could do three days with each of you and have one day a week that is a wildcard day he could spend elsewhere or toss a coin, whatever.