If your living with someone --how long is to long before you should ask the question or pack up and move out?

we dated about 2.5 years--E harmony--now we are living together-----I was activly looking for more partners while we aere dating...but always came back to her....I do not feel like I am in LOVE or will be able to love her---but it is comfortable to always have some one that is loyal and avaliable.......yes that kinda makes me a clod--but there is no secrets...what do you think stay or go??