In Japan, someone may be warm and affectionate when alone with their partner, but suddenly become much more reserved when parents or siblings are around. A person who normally holds hands or casually touches their partner may feel awkward doing the same thing in front of family and keep a little more distance. Sometimes, the moment family enters the room, “couple mode” quietly gets dialed down.
One major reason is embarrassment. Being seen acting intimately with a partner can feel awkward in front of parents or siblings, even when the same behavior feels completely natural in private. Some people may even sound slightly more formal or distant in the way they speak to or address their partner. That does not necessarily mean their feelings have changed. They may simply become more reserved when family is present.
More broadly, some people in Japan are uncomfortable with strong displays of affection or physical closeness in public, not only in front of family. Of course, this varies greatly by generation and personality, and it does not apply to everyone. Still, some people feel more comfortable saving hugs, cuddling, or other intimate behavior for when they are alone together.
It is not only about personal embarrassment. Consideration for the people around them can also play a part. Some people avoid strong public displays of affection because they worry that others may feel awkward watching them. In front of family, the embarrassment can become even stronger precisely because everyone already knows they are a couple.
If a foreign partner holds hands or gives a light hug in front of the family, some people may still feel awkward. At the same time, they may be more accepting because they assume that this kind of affection is normal in the partner’s culture.
So if someone becomes noticeably less affectionate only when family is around, it is better not to judge the relationship from that behavior alone. If they are just as close as usual when the two of them are alone, the change in front of family may have much more to do with embarrassment and comfort around public affection than with a lack of love.