You're lucky that she came around and that she's working in it!
Phew yes! I did mention the health issues too, but then she looked on the net, didn't want to risk a prolapse....
I have no desire to personally experience fisting, but I'm fascinated by seeing it.
I don't watch it, & I told her - this is way extreme; but it isn't about pumping away & causing pain!
Very surprisingly, it's very emotionally intimate - it's hard to explain - but even for a guy solely giving, you get a real bond, because you have to be that more careful, & aware of responses, & for the women, you're having to have a lot of trust, yet be so turned on.
In a way, it's more of a unifying experience than the vagina/penis penetration, because if you're giving, you're so aware that you are literally attached(!), & aren't lost in yielding to your own sexual needs.
I think Fisting is a poor name - Deep fingering perhaps?
You should try it (unless it hurts), but obviously when women have popped out a child or too, it's meant to be easier.
It sounds like she might be lucky to have found you, too!
Aw shucks - One day at a time, one day at a time!