Going only from what I've been told: it could be any or all of those, about
trust or
fear or
pain.
Emotions play a bigger part in sexual satisfaction than the
movies would have you believe, and even
moreso for
women. It's not a
stereotype to point out that most
men are primarily
turned on by visual
stimuli, while for women emotional
involvement is what's
most important.
Being celibate for two years isn't necessarily enough. You may need to be with someone with whom you're solidly emotionally secure before you can enjoy yourself again. You'll have to have some serious conversation with your partner about this. You may also wish to look into professional counseling for a short time to understand what it is you want and need. (No one likes the idea of needing a counselor, I know, but I also know that sometimes it's the quickest and best road to emotional healing.)