In most cultures and religions, touching one's spouse's feet is not considered a sin. It's important to understand that cultural and religious practices vary widely around the world, and what might be acceptable or even customary in one culture could be seen as unusual or inappropriate in another.
In some cultures, touching someone's feet is a sign of respect or affection, while in others, it might have different connotations. Similarly, in certain religious practices, foot-washing or touching feet may hold symbolic significance, but it is not inherently sinful.
In a marital context, physical affection and touch are normal and healthy aspects of a relationship. It's essential to respect each other's boundaries and preferences within the relationship. If either partner is uncomfortable with any form of physical touch, including touching feet, it should be communicated and respected.
If you have specific concerns about cultural or religious implications regarding this act in your situation, it is best to seek guidance from religious leaders or cultural experts who can provide more context and insight into the specific beliefs and practices involved. Ultimately, mutual understanding, respect, and communication between spouses are crucial in navigating any cultural or religious differences within a marriage.