Yeah I would suggest spicing it up as well, but you seem so.....blase' about it... I mean, long term relationships are not always about the thrill and the passion...once you're together for a few years, yes, there IS passion but it's not always the every-day-I'm-so-thrilled-you're-in-my-life-how-did-I-get-so-lucky kind. And it sounds from what you've posted, rather than becoming a lovely, comforting, mutually supportive and loving relationship...to you it's just a drag. Literally.

So, y'know....don't. Drag it out. Just be honest with yourself and if necessary, let her go so she can find a man she has the chance of meeting...someone who wants the same things as she does (including a long term, long lasting relationship if that's what she wants, or short term fun relationships, again, if that's what she wants) but end run...give her a choice. It's not fair to her, or to you, as was stated already, to just ....do nothing.

She won't thank you for it, when you do eventually tell her it's over. Oh, and don't make the mistake of hanging around until you meet the 'next great thing'. That's a 'safety move' and a cr*p bf move.

Take care