I need some help with 실례지만
Can anybody help me with this verb? I know that 실례지만 is the form of 실례하다. If so, why don't we say 실례하지만 like with other verbs with 하다?

Question

Answer

실례지만 is not from 실례하다.

실례지만 is a short form of 실례이지만 which is composed of
실례+이(다)+지만
실례 is a noun which means "discourtesy, bad manners"
이다  means "to be" 
지만 is a connecting particle means "though"

Equally, 실례다 in the following example is a short form of 실례이다.
여성에게 나이를 물어보는 것은 실례다 
It is not good manners to ask a woman her age.