When it comes to personal relationships such as you describe, I've found it helpful to think about things in terms of quality-of-life. For instance--and bear with me through this example--who does the laundry? Is it worth it to you to spend $100.00 month to have a laundry service take care of that so you and your partner can spend a couple more hours together without eating away at your other activities? For the purposes of this reply, I'm going to use the shorthand that "spending time with" your partner equates to more communication.
It's all about balance. As @THelper notes above, only you and your partner know if you are communicating effectively and too much/little. Does your partner feel that you communicate too much? If so, then find the balance where your communication is acceptable for both parties, and you may gain some time for yourself. Too little? Maybe you shave ten minutes off the triathalon training every day and spend it with your partner. Maybe you establish a meditation routine where you AND your partner take the time for stillness and quiet...and that stillness may lead to more intense, direct, honest, and more "efficient" communication.
Many people feel the realtionships end up in compromise. I've found that I rarely need to compromise, if I communicate honestly and openly, determining what our respective goals and needs are. Usually there's a way to mesh everything together, and I'm very good at figuring that out. With your quest for a rational way to compare individual and group priorities, I suspect you're similar in that regard.
The challenge you face is the balance between emotion (your partner) and logic (a rational way to compare). The reality is that once there is another person in your life that you have decided to make a priority, it ceases to be project management and becomes all about negotiation. It's no longer a hard skill of scheduling, but becomes about the soft skills of
I've project managed my entire life, scheduling things to the minute and have been very productive. My current partner is not so structured. I've decided the the relationship is important in my life, I've decided that it adds to my quality of life, so I structure my OWN goals around and within that context. Yes, I've compromised on some of my goals. Some of my personal projects and dreams are languishing on a back burner. But, that's a choice that I've made given a.) the priority in my life to which I've given my partner, and b.) the improved quality of life brought about by making that particular choice.
Considering the question that way may be a helpful way to frame personal and group goals.