sometimes when children have been forced to keep their pain/abuse a secret it becomes second nature to do just that, so as an adult rather than cry they burry the tears and true feelings inside, showing what they think others want to see
having someone care about you, really care by doing kind caring things for, to, and with you along with therapy will help bring them back to the surface, but be aware once they start they will come in bucket fulls along with a great sense of vulnerability.
i found watching films like Lorenzos oil, beaches or ones about parents fighting to find a cure for their dying children seemed to work too! seemed like watching what other parents would do for their children made me realise just how awful mine were and i would actualy feel deeply sorry for myself and cry really hard. i still find it difficult to make any sound when i cry, but the tears were like fountains for quite a long time once they began.

be kind to yourself, they will come eventually, when you are in a place where you feel safe x