When I went off the pill, I used Billings, and we used barriers (condoms) for the fertile times. Personally, I found the Billings was brilliant for me in terms of getting to know my cycles before we started TTC. We used these methods for about 10 months, then started TTC. I haven't gone back on the pill and I'm not likely to.
Is it too intrusive to ask what you find mood-killing about barriers? Condoms can be put on a bit earlier so you don't have to think about it at that cruicial moment, and while I haven't used a diaphragm before, I know they can be put in well in advance. If you have an understanding of your cycle, you could just use these methods onyl during your fertile times to prevent pregnancy...?