Croton Losing Yellow leaves

My husband and I received this plant as a wedding gift 9 years ago. We have no idea what it is or how to care for it. It periodically drops leaves and the leaves turn yellow, which makes me think we are overwatering it. But with 3 small kids and 2 dogs, I’m not sure how that could be, since we can barely remember! Please help us figure out what’s wrong! My husband and I jokingly refer to this plant as a metaphor for our marriage, so we must keep it alive! Haha!