I don't know if there's any npc romance that is as complicated as her's.
I have only finished the trooper story so far, but unless the other classes are radically different, decisions you make regarding your companions are already unimportant (from the moment they join in the case of Jaesa). All that they really affect are affection. And you can raise that with gifts to negate the fallout of any decision your companions did not like.
They tend to be more complicated in situations where you have more than one romanceable companions on your ship, where you get a confrontation and have to make a choice about it. You can definitely kill a romance or stop it from happening on at least most of them. There also are some decisions you make about the nature of your relationship (marrying, not marrying but staying together, and some other things specific to certain companions).
How important those decisions are depends on whether they ever continue companion stories, and how much you value your own personal RP experiences with them.