I don't know how much longer this relationship can last like this at it is pretty much asexual at the moment.
I'd say its going to go on until you die. You haven't left her yet and you knew that she wasn't much interested in sex from the first time you bopped her. She aint changing mister and it looks like you're not going anywhere. Six years and you're still putting up with "it is what it is."
Time will tell if you can go an entire lifetime with her without getting is elsewhere. tick, tick, tick
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion