@englishtchrivy: Thank you for the best wishes. I have seen a lot of children from mixed marriages in Japan grow up to be only passive bilinguals, and that is a fate I would like my children to avoid. Raising active bilingual children is a lot of work, especially when you are the only main native speaker in their life. Many people have recommended using TV and video to supplement their English exposure. I will continue to do so. Thanks again:)