3 words: communicate, communicate, communicate!
Sounds like he has as many fears around relationships as you do. The moving slow part actually sounds normal and customary (healthy) to me.
My situation is somewhat similar. We have found that writing down our triggers helps a lot. When I wonder what has set him off, or what has caused me to flip out... it's usually on the 'trigger list'. Talking calmly (no heated words, no personalizing the problem) about what triggered us seems to take all the fear and doubt away. Now, we're working on building trust - that will take years.
We see T's individually. Perhaps someday, we will see a couples T and work on our past.
Good luck and hang in there!!! Sounds like love...

VoN