We are following Domain Driven Design for the implementation of a large website.

However by putting the behaviour on the domain objects we are ending up with some very large classes.

For example on our WebsiteUser object, we have many many methods - e.g. dealing with passwords, order history, refunds, customer segmentation. All of these methods are directly related to the user. Many of these methods delegate internally to other child object but
this still results in some very large classes.

I'm keen to avoid exposing lots of child objects e.g. user.getOrderHistory().getLatestOrder().

What other strategies can be used to avoid this problems?