The email read, in part, "I am married and we're having trouble finding time managing our one unit as time is always a consideration. So I was just curious if in poly relationships certain people have certain nights, or how you avoid conflict if 2 of your partners want to do something with you on the same night or weekend. How are potentially emotionally charged situations avoided?"
My own experience with time management is likely to be different from a lot of other folks, because I don't really manage time; it manages me. ("In Soviet Russia...") As a result, I don't do Google Calendars or iCal or anything like that; hell, I can barely make it into the office at a consistent time each morning.
One of the things I've found in my own experiences in polyamory is that a lot of time management issues are resolved quite nicely when partners get along with one another and with the partners of their partners. I've found that relationships do need a certain amount of 'alone time,' and that having two partners can mean having less time to spend with each of them--but not nearly as much as you might suspect. Since it's possible to spend quality time with more than one person, having two partners doesn't mean that each of them gets only half your attention.
In any family, even a conventional nuclear family with two adults and a couple of children, it's always possible to have scheduling conflicts. What do you do if your spouse wants to go see a movie, but you'd rather stay home and catch Battlestar: Galactica on TV? What do you do if your child has a school play on the same night that your spouse is due to receive an award from a professional organization? These kinds of problems can happen in any home, and reasonable people can find reasonable ways to accommodate everyone's needs. The same is true of a poly relationship.
To use a real-world example, I have had a situation where one partner wanted to go out dancing and another wanted to go to a movie. Simple solution: all three of us did both.
Part of being a reasonable person, in any kind of relationship, is accepting the fact that nobody gets everything he wants 100% of the time. Flexibility is important, and I suspect that flexibility is actually one of the keys to happiness, no matter what your relationship structure looks like.
Another good tool in poly relationships, which is valuable but often overlooked in any relationship, is the notion that you can't expect to have what you want if you don't ask for what you want. Often, people will make tacit assumptions about the behavior of their partners, without actually clearly saying what their expectations are, and then become hurt and angry if the expectations aren't met. It's not enough to say "The new Batman movie is coming out next Friday;" instead, it's important to communicate expectations clearly, and say "the new Batman movie is coming out next Friday, and it's really important to me to go to the opening with you." Just that little bit goes a surprisingly long way toward helping to resolve scheduling difficulties and hurt feelings.
In some poly relationships, people do set up regular "date nights" with specific partners, so that everyone has a sense of what to expect from the schedule. I don't do that myself, but then, I'm not much of a scheduler. For folks who are, that's an awesome tool to help let everyone know what to expect--though I would say that it's also important to be somewhat flexible about it. Life isn't always tidy, and should a conflict come up or should a partner become ill or injured, I think it's reasonable to be able to rearrange the schedule without causing undue grief.
For me personally, I like spending time with all my partners, and I like having the ability to spend time with more than one partner at once. I also do not feel cheated or like I have lost something if my partner's other partner goes along too. For example, I really enjoy going out to dinner with my partners and their partners as well. Part of healthy, successful polyamory, I think, is in knowing and accepting that not all of the time you spend with someone will be one-on-one time. (And frankly, I think that's a benefit; I've met some awesome people through my partners, people who have become my friends independent of our connection by dating the same person.)
Any relationship can have time management problems. A person starts working longer hours at the office, a person picks up a new hobby, a person starts spending more time with friends, a person starts playing video games--when these things happen, nobody really asks questions like "don't you have trouble managing your time?" Nobody (well, nobody I've ever met, anyway) says "If you start taking up photography as a hobby, I am going to want to start scheduling the time you spend doing it, because I want to be able to limit the amount of time you spend away from me." Polyamory's no different, yet we often see it as different. Good time management skills are the same regardless of the nature of the demands on one's time. It feels different when we think "My lover is spending time with her other lover" than if we think "My lover is spending time in the darkroom," yet from a practical perspective, the same sorts of tools for managing time still apply.