i just posted another reply in the permament damage section - but - listen - with reference to sex and propecia - (i have become somewhat of an expert) - i know that women who are wanting a child or are trying for one should absoutely NOT tocuh the active ingredient which in this case is Finastride. Remember that if you as an individual experince ill side effects you should stop taking the medication.
Regarding sex - just be careful...if it really bothers you to wear a condon then maybe you hsould stop taking Propecia...
If you are in a stable relationship and you are having unprotected sex then surely your partner loves you for being YOU - so - with that in mind why are you taking Propecia if you are concerend with unprotected sex...anyways just food for thought