I am reading a good little book called, "Soul-mates.  How to Find Them and Keep Them." Here is an excerpt I would like to share which I can sense is what has happened to our marriage:

""...when you allow a person to continually take more than their fair exchange, that person will become critical and hostile towards you. The mechanism of justification kicks in and they have to attempt to excuse their misdeeds. This usually involves degrading you. When someone commits acts which they know are harmful, the mechanism of justification dictates that they then attempt to blame or criticize the person they have harmed. Rather than look at their own failings and acts of negligence or directly harmful effects, the individual attempts to direct the attention to what other people are doing, most especially the one that was harmed."

The gist is that a good relationship needs to have balance.  Are you giving much more or much less to the relationship than your partner? Just some food for thought.