"Unconditional love means love without condition, yes? Love without requirements, free of oaths and contracts, expectations and attachments. Love that is offered without the anticipation of getting something in return. Love that does not need to be coddled or catered to, in order for it to flow. Love given free of contingencies or qualifications. A Love impervious to approval or disapproval."
Source: Elizabeth Reninger. "Unconditional Love." Taoism.about.com.
For many, in real life, unconditional love is rare and is considered an idealized love. Many think it is reasonable to have a mature and deep love for your spouse that has conditions. Most individuals have a line that if crossed is a deal breaker in their marriage.
For some, a belief in unconditional love can trap them in abusive situations.