In the past this same scenario plagued dh and I also. We were together about 3 years at this time, planned on getting married but were still quite young and were waiting to save up money for the wedding among other things. In the meantime Dh (bf at the time) got a job that allowed the domestic partnership on medical ins. The rules were that you had to have lived together for atleast 1 year and share a bank account, there was also an additional $20 fee he was charged each pay period for my being on the ins. It worked pretty well for us since we fell under the guidelines. It was me who really needed the health care, I have issues that require consistent medical care, blood level testing, medication, access to specialists, etc. My sister also worked at the same company and she was happy with the domestic partnership rules here, this was the first place she could have her girlfriend/partner on her insurance, she really felt like society as a whole was becoming more accepting.
Unfortunately that company closed. Dh took a job at sears until he could find another job in his field. When benefit enrollment time came he jumped at it because we had been without ins. for a while and my out of pocket medical costs were rising, my job didn't offer p/t employees benefits at all at this point. We quickly found out that the only domestic partners sears would allow was for gay men and women (at the time, it may be different now). If you were not of the opposite sex as your partner you were not elgible and this was the only requirement other than having to had lived together for 6 months prior to enrollment (although no proof of this was required).
I have no problem with domestic partnerships (I was in one) but I feel that regardless of sexual orientation of the partners, each partnership should be created equal. It shouldn't be about who is in the partnership, 2 men, 2 women, man and woman, etc. at that point I was a little upset that one partnership was recognized and one was not, both should have been acceptable. I didn't feel like we were punished for not being gay but it was like a kick in the face. I agree that domestic partnership laws do need some tweaking but overall I am glad they are in place more often and at more places of employment these days, I mean geesh, it took long enough to get them implemented at all.
note: We found an outside insurance that allowed domestic partners to the tune of $280 more per month (than if we were allowed to purchase through dh's sears job) but we had no choice so we took it