That's it exactly and he knows Jack can read his body language enough to see he's got it exactly. He doesn't want to be controlled by this and if there is anyone who he wants to work through it with it's Jack. He makes a mental note to thank Martha for pushing him on the honesty issue.
"I feel ready if it's with you." and if it turns out he's not ready he feels like he can go through that reaction with Jack as well.