Note: this is a growing field, with more resources being created all the time. This list is neither comprehensive, nor particularly in depth in various directions. I am simply attempting to provide a good starting point on various topics. As always suggestions are welcome.
Best, biggest resource list: http://robinstoynest.com/Toys/ready-sexy-able-sex-and-disability-resources/
more resource lists: http://sexuality.about.com/od/sexdisabilityresources/
Excellent, very thorough book: http://www.barnesandnoble.com/w/ultimate-guide-to-sex-and-disability-miriam-kaufman/1102331174
resources for sex ed for people with disabilities:
very basic intro for women with disabilities
lots of useful basic ideas + links to lots of support groups
Archives of horizons magazine relating to relationships and sex
Radical Sexual education tumblr for all topics:
Resources specifically for educating partners:
For FM/CFS/ME: http://fmcfsme.com/family_friends.php#donthear
For everyone, article on positive communication: http://www.telegraph.co.uk/lifestyle/wellbeing/6207548/Now-youre-talking-making-relationships-work-through-positive-communication.html
For more information about how to identify unhealthy relationships I have another resource sheet here.
Two studies looking specifically at backpain, sorted by women and men but can be applied more generally.
Resources for teachers