can i get pregnant if my guy is using drugs?

hi im 23 years old and im already married we been trying to have a baby for the 3 weeks. we are far from each other his in the other side of the world. we just try to have a baby when his here and we been trying to have a baby for 3 weeks that he is w/ me. but im still not pregnant and i found out that he is using a drugs.Do that drugs affect his sperm?