I had some very similar thoughts to you. I did not want an epi at all and I only wanted my husband at the birth. I had a hard and fast labour with no break in contractions from the first to the last with a lot of back pain. I remember thinking during that time that I could understand why people opt for an epi, it is HARD! I reminded myself that it wasn't going to last forever and millions of other women had given birth before me. I found great relief in water injections in the back (saline injected just under skin in four or five different sites). It relieved my back pain and I founs things so much more bearable after that. I wished I had done them so much earlier. Apprently they can do them in the tummy too but most people don't ask for that.
I only wanted my husband at the birth. I was worried aobut offending my mum but explained to her that I didn't know how I was going to react and I can get snippy when in pain and I didn't want to be concerned about offending her. I asked that she be at my house though so if I did need her she could come up to the birth centre. We were home within 2.5 hours of the birth and mum got to have a lovely cuddle of our new little baby then. I think she was fine with it although I am sure that she would have loved it if I had asked her to be there too. I have no regrets about the birth experience and would do it the same again. It was lovely to just have my husband and I there.