DP is always so bloody secretive about his phone, deletes all messages, keeps it glued to him etc etc. This morning he accidently left his online acount open and it shows that he text his ex wife 12 times just yesterday. Every time he must have done it in secret because I didn't see him text anyone all day. He has a tendancy to take it into the bathroom and text whilst in there 
They do have a child together but she's 15, lives with DP and tends to sort all access stuff out herself directly with her mother.
AIBU to think that texting your ex 12 times in one day and often in secret is a bit dodgy (coupled with the other secretive behaviour).