I saw a good link for this question a while back. If someone could just direct me there, I would be very appreciative.

Terrence Wade gives this example:

Она привыкла к тому, что мужчины на неё заглядываются.

Wade only gives the example and does not discuss it. Is the need for "то, что" strictly because the verb demands a prepostion? Is this the only reason to use this construction?