TweetIt is all relative to how much you take, but for the most part the answer is "No." Anastrozole will not affect you sex drive much, if at all.
Anti-estrogens can cause a downturn in sex drive if too much estrogen is neutralized. Estrogen in men is not all bad, and a certain amount is necessary to maintain a healthy sex drive, among other things. Letrozole is a powerful steroidal (permanently binding) anti-estrogen that can take your estrogen levels below that threshold, and thereby reduce or elimintate the libido. Anastrozole is a weaker non-steroidal (but still effective) anit-estrogen that rarely produces this effect. This is because a typical dose of anastrozole is not enough to drop your estrogen levels so low.
It is worth mentioning that these are but two of the many options we have for the purpose of combating estrogen. Many people actually prefer exemestane or proviron while on cycle, though each anti-E has different chemical properties and is useful.
I hope that this explanation helps.