Hmm. I suppose one could look at topping one's Dom/me as merely an order to follow through on, however, methinks that's wandering into some very sketchy territory if the sub has no natural inclinations to switch.

I don't have any issues with Dom/mes that switch or have a passing curiosity as to what it feels like to be a sub. The problem, as I see it in cases like the OP's, lies in the fact that Domming and subbing is more than who happens to be wielding the crop at any given time. It's a hugely mental and emotional headspace.

I could "act" like a Domme at my Master's command, certainly, but it would never be more than an act and that in and of itself would lend an uncomfortable sense of falsehood and illigitimacy to our intimate relationship. Not good. I know I can't submit to just anyone, so as I was going through the motions I would also be wondering how my partner could be truly submitting to such a false mock up of a Domme. "Is everything we do just an act to him?" I'd wonder. More doubt. Again, not good.

I could go on, but I think the point is made.

Perhaps a compromise could be made, however? I myself have a pretty strong streak of top in my nature. I have a largely Dominant mindset around most people and in the majority of my past relationships. Sometimes that flares up, and my Dom plays along for awhile before "putting me back in my place." It's a game that allows some switching to happen but in the end re-establishes the balance of power to where we are both happiest.