I think it depends. If it feels better to you to imagine this relationship to go on, it is worth saving it (and I think it really doesn't matter which legal state your in, married or just living together).
The point is that marriage was NOT invented by God, but it was construed as a purely practical means to a) ensure that the wealth stayed in one family, b) the offspring was from the male spouse and c) to take care of the mother. Main reason was always to acquire and maintain wealth. That's why there are many cultures, where marriage is a solely economical thing, the woman has to bring enough money with her to get into the family.
In our modern culture, reasons to maintain a marriage or a relationship are as varied as the people who are in them. I think it all melts down to how you feel about the relationship. If it makes you feel good and you think it is worth maintaining, you should do it.
If you think that it would have to change fundamentally in order to work, my advice would be, forget about that. Nobody really changes, we don't do it ourselves in most cases, but we tend to expect it from others. It doesn't work.
Try for a while to collect all positive aspects of your relationship, make lists of it and look for things to appreciate. If this doesn't work, it may very well be time to move on.
Best luck to you,