There is a sense of major, life-changing mission at work here. A plan has been hatched, imagination has come into play and the querent is working out how best to make the break. Considering the way forward is an important part of the process - it's not wise to make huge alterations before considering likely consequences. The Six can arrive as a warning to the querent to think things through carefully before acting. Alternatively, it could be a comment on the self-doubt the querent is doing battle with. Making big changes for the better is scary territory and many people would gladly 'sit on their hands' and deny the issues they're having, rather than face that things aren't right.
The Six of Swords tells us that we should never feel trapped. There is always a choice, no matter how difficult it is to make. I've always felt that this card has a message of self-love inherent in it too. Sometimes we stay put for other people and fail to put our own needs first, but there is a breaking point inside every single one of us and when we reach it we know that we have to do what's necessary for our own happiness, no matter whose nose might be put out of joint.