From a game standpoint, I view inflation simply as part fo the cost. Everything costs more as time goes on. In 'real money' terms, then, if you economy doesn't expand/increase your real purchasing power declines. The critical issue is recognizing how costs work. Yes, you may have to disband military forces as the game goes on if your economy doesn't grow.
Don't forget there are some game ideas that help. For instance, if you take overseas cities, it is often a VERY good idea to liberate them; your trade with those cities is now worth a different country, increasing the value of trade substantially; moreover, you don't have to pay the horrendous upkeep costs. Late in the game, with a large empire, city states is often a must Civic. (In regular Civ, you need courthouses, etc.
Best wishes,
Breunor