Punjab, Sept. 9 -- Couples talk about money late, and usually in the middle of a decision rather than before one. The conversation is not fundamentally about how much each person earns.

The assumptions that cause trouble

Most conflict traces back to unstated defaults each person absorbed from their own family: whether money is for security or for use, how much support is owed to parents and siblings, whether debt is a normal tool or a failure, and who is expected to decide.

In Indian households the family obligation question is frequently the largest one and the least often raised directly. Two people can agree entirely on budgeting and still be far apart on what a sibling's wedding or a parent's medical cost has first claim on.

Three q...