I have only just gotten the Mirena put in as for me i felt it was one of the easiest options.
Not having to remember to take a pill, was safe for BFing and not havign to regularly go to the Dr or have something inserted.

It was uncomfortable when he did it but now you can't feel a thing, don't even realise it's there.
I spotted for a couple of days afterwards but that was it.
DP and i have DTD and he couldn't feel anything, TBH as gross as it is i have had a feel around and i can't feel anything.

If your OH does manage to feel it they have said they can trim the wires.

I can't answer most of the other questions but i am HOPING that nothing goes wrong and that this is right for me, maybe have a chat with your OBGYN and see what they say, voice your concerns and ask for stats?