I doubt you are that valuable. Sure software developers are high priced, but without even knowing what company you work for I bet I can do your job at a competitor and after 3 years I'd be just as good - that is worst case when I have to learn a new programming language to expert level as well as the domain. There are only a few people who have special skills that it is even worth thinking about protected. Someone who hires you away from a competitor gains at most a couple months vs hiring someone with similar skill who doesn't work for a competitor (and thus doesn't have domain knowledge).
