My wife of 14 years did the same thing to me a couple of years ago out of the blue so I know how you feel.

My recent relationship has gone down the toilet and I truly believe that 90% of the reason why is that we could never talk privately and without time presures. I swear I think we could have worked it out if it had just been she and I alone without kids screaming, office phone calls, watching the clock etc.

The only advice that I can give you is to talk privately, probably in a netural place away from any outside pressures.

Best of luck....