Complex sentence: Tysha found Tyrion pleasing, and they wed in secret, but when Lord Tywin found out, he explained that she was a prostitute whom Jaime had hired for Tyrion's benefit.
Split into simpler sentences: Tysha found Tyrion pleasing, and they wed in secret. When Lord Tywin learned of this, he explained that she was a prostitute whom Jaime had hired for Tyrion's benefit.