Yes, she is hard to like, alright, but Lyndsey Coulson's acting keeps her just this side of likeable for me.
I don't think her recent behaviour gives David an excuse for being unfaithful, for several reasons:
1. He's known her all their lives and knew exactly what he was getting into this time around;
2. Her cancer entitles her to be miserable at the moment;
3. She's behaved coldly towards him because she mistrusts him - for very good reason as he's cheated on her time and time again.





