Problems with Insanity
My character met for the first time an entity that is covered on fire. For that reason, the DM (as I took sanity damage enough to get indefinitely Insanity) decided that I would become pyromaniac. I don't want it to turn me into a "Dumbass pyromaniac" and I want it to turn into something more interesting for the development of the character. My character has good alignment and has the personality Coldblooded. Any advice on that?
Additional info: The context is Seattle, USA 1995. My character is normally friendly, but gets really focused/coldblooded in danger situations. There are two dimensions: The normal world, that it's just like real world, and a "Reverse world stranger things"ish where the unnatural stuff happens
A little bit more info: I'm planning for this pyromania to be a core part of his identity, but not to show much of this slow decay to the rest of the party (I really want to keep it more sutile and it keeps getting more part of the personality). And more importantly, I don't plan my character to become really crazy dumbass'ish ever during the campaign, but the struggle is real.
Lastly, I want this fixation to be a thing that the character fights constantly, like resisting to the temptation, trying to run away from any fire with the fear that if he doesn't he wont be able to hold himself from doing something really terrible.