I didn't have one with DD and probably won't next time either. DH and I discussed the various pain relief options and possible complications that might arise and agreed on a general approach. He was then able to confidently assist me and make decisions at the time. We also had a great OB so in the case of something going wrong our plan was "whatever Dr B says goes!".
I have no regrets about my birth experience and I think that's because I was willing to be flexible and go with what works at the time - which turned out to be quite different to what I expected I'd want to do!