Does anyone know how to hack a HTC phone? I need to get into one but there is a lock code.?

My bf is soooooooooooooooooooo over protective over his phone and its so annoying. He has a HTC but theres a lock code on it but he set it to where I cant see the lines that appear in the screen when he puts it in because I always use to figure them out. Now that I cant see the code I cant get in the phone I need to see whats going on in ithat phone, weve been together for too long for any childish games be be going on ive tried to talk to him about it time and time again, i didnt want to have to take it this far but I see I have to. He obviouslty has something to hide because if he didnt he wouldnt be so over protective. I never bug him about having my phone because i have nothing in there to worry about. someone please help me hack it.