Hot plates can be kashered for pesach. The process is listed on the star-k’s website. The gebrokts avoider could get his own hot plates for cooking, his own pans and plates and essentially make his own kitchen. As someone mentioned earlier, BTs and gerim are all too used to this kind of problem.
I agree with Joseph that “eat off the keilim anyway” is a non-solution.
Also, for the record, the minhag of kitniyos trumps any concerns about shalom bayis any day. Avoiding kitniyos is an extremely important minhag, it is not at all comparable to gebrokts.