I too would like to see some ClaireXBlaire. Maybe leaving claire for someone else would be interesting.
And as for why claire would get mad. I think she does because sleeping with her doesn't really do anything to benefit them? Like if you play as Paul, she either doesn't know that your sleeping around and when she does, its for something revolving the debt or to make allies? Sex with Claire doesn't really do anything to help the situation, so maybe thats why she got mad? Thats just a theory 馃