Early in the play Othello worships Desdemona and eve foreshadows himself becoming Mr. Crazy should his love ever change, "But I do love thee! and when I love thee not, Chaos is come again." Othello then takes the fast train to paranoid town. Sure he loves Desdemona as far as he has branded her his. When his ownership comes into question, his love and very identity become a violent tempest. It's the old Madonna/hoar syndrome that many of Shakespeare's leading men had. Othello's was particularly bad. He needed to worship Desdemona. When he feels in danger of becoming the dreaded cuckold, he snaps and Desdemona comes tumbling down from her alter.