Congratulations! You have a partner who likes some of the same things you do. Now you get to find out some of the different things you each like to do. You mentioned that he is currently deployed. For that I say thank you for your support of him and his mission, to him I say THANK YOU, SIR! for his sacrifice and service to our country.
If he is currently serving in the sandbox you may discover that his pain tolerance is greater than you think. What you think is very painful he may consider a slight annoyance. AND there may be even better news (having nothing to do with his deployment) - he may be holding back because he doesn't want to hurt YOU! (I have a problem with that myself) So do a brief setting of expectations before, then after - not immediately after but maybe the next morning, do a debriefing and see what worked well, what worked poorly and what not to do. At this point if things don't go perfectly you get a do-over, a mulligan in golf parlance. That's the GOOD NEWS because it's a reason to do it again! After all, practice makes permanent. And if you like what you practice...practice some more. Would you be totally turned off because he did something you didn't expect, or didn't like and never want to participate again because of it? Neither will he. Relax and enjoy it. Before you know it you'll be swinging from the rafters by your heels with your tits full of skewers while he crops your ass and you suck his cock. Or something like that. Remember to post the pix.