Dreaming of a brothel means you are sexually active and have an urge that is unfulfilled. You will need more physical contact from your relationship once you have started dating. Once triggered, the only thing on your mind is seeing your significant other to get closer to them. You long to hold them each time you meet.
Your desires are not being met because your other half may not be in close proximity to you. Your mind is implying a temporary solution to getting your desires met because you lack self control.