Omg!why is my dad sending these messages??!?

[mirabelle]

im a 13 year old girl.i have no siblings or close family.i live with my 2 married parents.
im not gonna confront my dad or tell my mum(shes bipolar).

on my dad's phone(blackberry bbm):
"thats a sexy profile pic,makes me wanna hold u.love u babes miss u too xx"

"awww thanks sweetie love u too xx"

"you will always have a place in my heart and i will always make time for u"

in another convo on his facebook with the same woman:
"cant wait to see u hunny xx"

"miss u so much x"

in another convo:
"just got out the shower"
"wish i was there to dry u xxx"

its definativly not my mum or family.i checked her profile:
i have her phone num,home address,name.
she lives an hour away from us.shes in her 30ies.
my dad is 51 years old and is a protestant preacher!

who could i speak too?what should i do?

btw i took snap shoots so i have proof.i know it was wrong of me to look in his messages.:-(

IM A NOT GONNA SPEAK TO MY MUM OR DAD ABOUT THIS

[Gina]

Why are YOU spamming this question? We aren't psychic. The only person who knows what your dad is thinking is your dad. If you won't ask, youve resigned yourself to never knowing.

[Jan409]

Sounds like you've made this all up
People having an affair don't leave their phones lying around for everyone to read their messages
Try again...

[Emma]

I know you don't want to talk to them about this, But I think you should definately say something to your Dad. He can't do that to your mum, especially with her condition.
Confront him and tell him you have proof. Make sure you back-up the evidence incase he gets his hands on it.
Use the 'If you don't tell her, I will' technique!
Hope it works out, if your worrying that much, tell someone x