Yes, a married couple can kiss on the lips in Islam.
In Islam, intimacy between a husband and wife is considered a sacred and blessed act. The Quran and Hadith encourage spouses to engage in physical affection, including kissing. This is seen as a way to strengthen the bond between them and to express love and intimacy.
However, it's important to note that Islam emphasizes modesty and privacy in matters of intimacy. Therefore, public displays of affection, including kissing, are generally discouraged.
Ultimately, the extent to which a married couple can express affection is a matter of personal preference and cultural norms. As long as it is done within the bounds of Islamic teachings and with mutual consent, kissing on the lips is permissible in Islam.