I discovered that my boyfriend is addicted to drugs?

Get away from him: Please forgive my frankness. If you've been in a relationship with him and he's concealed this, the outcome of the relationship will almost certainly be disastrous for you. Get guidance from friends and good counselors and escape safely.

What is the question: you are asking? Many (most) people with alcoholism and other drug addictions manage to keep it hidden, even from loved ones and co-workers, for long periods of time. You have to decide whether this relationship is important enough to you to keep going. If his drug use is affecting you, tell him of your concerns. Try attending some Alanon meetings (a 12 step self-help group for family/friends).