If you can't afford a couple hundred bucks a year then yes, you should consider carefully if you should perhaps demit until such time as you can.
I agree with others here that if this is or will be a one time occurrence you should speak with your lodge about working out some sort of arrangement, but if it's not I don't agree that the lodge should attempt to support your dues for more than that. You need to be able to support yourself.
This part is none of my business but I'm going to mention it anyway - you say your wife makes significantly more to the point where she has a financial advisory, but you guys keep the finances separate and you can't afford $15 a month. Something is really off here that probably needs to be addressed before you start worrying about paying lodge dues.