Don't know WHAT your doctor is on about...my GP (experienced in coil fittings) put mine in and they knew I was keeping it in for " a while" but took it out after 2 years. Any Family Planning Centre these days should have a qualified "fitter" (sounds like a car mechanic
) and is free. The Mirena Coil was brilliant...
As for diaphragms, not scary at all. They have a ring on the outside of them to hold them in place, and look like a rather large, flat space-disc (those sweeties that were filled with sherbet? But flat and not tasty, or so I would imagine). I found it dead easy to put in, and you can put it in a couple of hours before sex so it doesn't "kill the mood" but you have to top up the spermicide with pessaries/tube of gel (pessaries are the way forward)
Very amusing at times (personally I used to giggle like a loon taking mine out cos it tickled, but don't take my experience as wrote as I am a bit odd at times) and kind of messy but ... I went overkill on the old spermicides as it was NOT the time for me to be getting pregnant, but it went ok.
Diaphragm will need a fitting - you go, get measured (I know, I know...it's nothing like getting a wedding dress though) and then handed a rubbery bouncy thing. Has to be well looked after, washed etc. carefully and all sorts, but it's not the worst thing in the world.
Femidoms - those were the worst contraceptive EVER invented...