Complex sentence: It was rumoured that his wife once caught him in a hotel room with another woman and Gagarin jumped out of the second floor window and hit his face on a kerbstone, which resulted in a deep cut above his left eye.
Split into simpler sentences: It was rumoured that his wife once caught him in a hotel room with another woman. Gagarin supposedly jumped out of the second floor window and hit his face on a kerbstone, which resulted in a deep cut above his left eye.