Are your unhappiness a sign of a bad marriage?

A successful relationship is not necessary a happy relationship. Relational success can be measured in growth. The Imago theory shows that you choose a partner to trigger you on the place where you need to grow. Growth is not to become perfect, but to become who YOU are: unique, fully alive, relaxed and joyful.

How do you know that your relationship is on a growing curve?

A smaller gap between the polarities of imploding (quiet, sulking, freezing) and exploding (overemotional, fleeing, attacking). If the quiet one become more alive and the chaotic one become more calm, then you know, the relationship is doing its work.
If you realize you are expressing live that you didn’t do for a long time. I.e. having your say or showing emotions, or doing something on your own.
You handle conflict quick and effective
You are less reactive (less noise, freezing or sulking)
You are more grateful
You feel more alive
You have less addictions (less alcohol, drugs, eating, sleeping, computer, pornography, work etc)