My husband acts in a very similar way. He suffered a very traumatic childhood. He struggles with believing he could be loved, so the minute there is any strife he puts up defenses including numbing himself to the situation, dissociating, putting all the blame on me, invalidating my feelings, etc to protect himself from the fear I might abandon him. He tries to convince himself he doesn't care about me. It also took him a long time to realize he was doing this, but he is getting help now. The process is long and painful, but I know who he is outside of these issues so I'm committed to loving and helping him.
If your husband is traumatized by losing an ex in an accident his fear of losing you may be causing him to push you away in the same way when conflict arises. In this type of situation, it is ironically his love for you causing the reactions. He is afraid of the pain that often comes with loving deeply. If he isn't working to get some help then the relationship will probably be very difficult to maintain.