Re: I think my girlfriend is cheating on me.

You can ask her, but why would she admit it.  

Get her phone, and go through it.  You find out right away if she is or is not.   Problem sovled.  

Anyone who cheats will keep their phone with them at all cost.  When she took a hot shower, did she take her phone with her.  

Modern phones keep sent, drafts, deleted messages of all text.  Most people who delete the inbox.  Call logs?  

Is there a password on the phone?  Thats another sign.  

Also, and this is graphic,

if you are about to have sex with her, and you notice her clit is 'puffy'    That means she just had sex with another guy.