Through the Broken Window

Here are two topics I have been thinking about lately:

A Coasian approach to abortion. For me, it seems that this issue has to deal with property rights and the infringement of those rights. Obviously there are not zero transaction costs, but we are dealing with reality here. How would one come to an optimal decision and how does one negotiate terms of compensation, when one party is unconscious or incapacitated? I think I actually like Walter Block's approach to this subject as I stated a couple of posts ago, but it's the difficult topics that are the most interesting...
In the news: South Dakota to ban abortion and Birth Control without prescription.

The other is related to a topic Dallas brought up earlier. Is it a violation of the Libertarian ethic to cheat on your significant other? Since marriage is an explicit contract, I am mostly concerned with individuals who are dating. There would, at least in many cultures, be an implict contract involved with dating -- one implying fidelity or at least limiting any attempts as polyamorous activities. Since it is dating though, there are risks involved with this activity and should all infidelities on the part of a 'significant other' be considered an assumed risk? I suppose if this sort of issue is never talked about, there can only be limited expectations, but there likely still exists an implict contract -- even if it is one-directional. How do we resolve that and is one party deserving of restitution in the case of infidelity?

Any one want to take a stab at these?