This is one of the biggest disadvantages of foreign exchange market. Due to the decentralized and de-regularized nature of the foreign exchange market, it is dominated by brokers. And you actually have to trade against professionals.
Being broker-driven implies that the forex market might not be fully transparent. A trader might not have any control over how his trade-order gets fulfilled, but you may not get the best price or may get limited views on trading quotes as furnished by your selected broker.
So a simple advice is to deal only with regulated brokers who fall within the purview of well-reputed regulators [List]. The market is not controlled by the regulators, but they can control the activities of brokers.