In Islam, every husband should try his best to treat his wife in a very kind manner. Part of his kindness towards his wife, the husband can use flattering expressions such as the ones referred to in the question even if the expressions used are technically untrue.
Sheikh Muhammad Al-Mukhtar Al-Shinqiti, Director of the Islamic Center of South Plains, Lubbock, Texas, states the following: “Compliments between husband and wife are highly recommended in the Shari`ah, even if they are based on exaggeration or flattering. The Prophet (peace and blessings be upon him) is reported to have said: “Lying can be permissible in three cases: war (for deceiving the enemy), reconciliation between disputing people, and the compliments between husband and wife.”
What you have said fall under the third category mentioned by the Prophet (peace and blessings be upon him)—all what you said and other such invented compliments you use are poetic language, which should be praised and not discouraged.
The well-known man of literature Al-Jahiz said, “The most elegant form of poetry is that which is based on ‘lying.’” He meant that exaggeration, metaphor, and other figures of speech are components of the poetic techniques.
Therefore, there is nothing wrong with a husband saying to his wife “you are my soul” or any similar complimentary expressions even if they are technically untrue.”