Seems like it boils down to accountability and how much either of you are willing to defer to others....ehhh...preferably with minimal regrets 
Obvious to you maybe, but to him, the expectations of all a partner's role entails is probably quite daunting if not totally overwhelming considering time, energy, & logistical constraints.
Remembering that feelings about your plans & intentions are much easier to alter than emotions surrounding (past) experiences may help put things in perspective. So, agreeing upon realistic expectations based on guesstimated stress limit factors, can map the emotionally loaded labyrinth minefield of ultimate responsibility.
Just for fun, play out possible "what if" scenarios using non-violent communication or violent communication for that matter
anything beats non communication 

Is he a light-hearted type? Build his confidence with Ad Lib style multiple choice birth stories. Visionary? Try improv role playing. What inspires, nurtures, & moves him? Got power struggle issues? Try Takeninhand.com for restructuring your dynamics. Time to get creative and find a way to connect with him! You've got less than 6 months to cram & plan... 
Find your comfort/doable zone somewhere between full responsibility and (forgiveness) of a possible fatality, and trusting others to influence/create a positive outcome for and with you.
Personally, we would rather deal with our own fallibility, and hold ourselves accountable for all possibilities, than to wonder why we thought someone else could act as a better safety net. 
Especially when regrettable/preventable stuff happens, we always feel worse if it resulted from someone else's actions or influence.
That's just us though...
The considerable amount of research and preparation has been well worth it to us. Not to mention all the hilarious/hysterical/bonding times to be had! 
Soak up the immense wisdom of these passionate women http://www.wombconference.com/ Keep your motivational drive high! 
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