This sounds very familiar to me...my ex and I lived together for 11 years and never really fought. And in the end, I think our mutual fear of confrontation is what ended our relationship.

I don't think fighting is necessary for a good relationship, but if the reason you are not fighting is because you are afraid of confrontation, and that causes you to not express your concerns and needs, then it becomes very hard to maintain a healthy relationship. In my case, we both got so used to not asking for what we wanted that we drifted apart, finding other ways to get our needs met.

If you two really just have nothing to fight about, then you should just be happy that you have found someone so compatible. But, if you think your lack of fights may be due to you both suppressing your own needs and desires, then maybe you'd be helped by talking to a counselor, who could give you ways to voice your needs without it turning into a fight.

Good luck.
mj