Ok, I'm a fan of Barcelona, but pls lets see the things impartially, because you don't.
The reason why Real(and other teams too) have many cards against Barcelona, is because Barcelona always have like 70% possession of the ball, they pass the ball all around and that's annoying for their opponents, so they are getting angry and aggressive and make so many fouls(like real always do against Barcelona), and the ref have to stop that by booking them with cards.
So, if you'll ever be impartially, you'll remember that game Chelsea-Barcelona 4-2 when at the last goal of Chelsea, Carvalho fouls Valdez, and the best ref of that period didn't see that. And not to speak about last year semifinal Inter-Barcelona, when Milito scored a goal from offside, and in second game the ref canceled a valid goal of Barcelona. Without that "help" from refs, maybe Mourinho couldn't win UCL last year.
From now on when Mourinho/Real will accuse Barcelona of cheating with refs, try to remember that.
I don't blame the refs of cheating when they did that mistakes against Barcelona in 2010 semifinals, because they are humans and they make mistakes sometimes, but you, fans of real/mourinho always follow him from his press declarations, when he try to blame everybody for losing a game, but when Mourinho is helped by a ref, no one does like Mourinho do in press conference.