have you ever looked in your partners cell phone

No. Never have. I can't say never will, because I don't know what will happen in the future. But I am trying to refrain from looking for as long as I can. If I can't trust my partner, how will our relationship survive?

I looked in the call log once. Someone was calling in the middle of the night and hanging up when I would answer. I called it back and they never said anything. I did a reverse lookup online and found out who it was. I called their home phone from the cell phone and left them a message. That was the last I heard from them. I don't make it a habit of looking at his call log or text messages. I have no reason to think that he is cheating on me. If he leaves it sitting on the table where anyone can open it and look at whatever is on it then he'd got nothing to hide. If he starts sleeping with it in his pocket, well, then I guess we'll have a problem lol.

I have looked into my ex's phone and I did find some text messages that made me wonder and caused some fights break out. He claimed the love based text messages were to his roommate not him cause he let his roommate use his phone. It made me very suspicious.

I hate to admit it, but I did...once... She is my ex now, for many reasons...but I am glad that I looked...She started to get overly protective of her cell phone, carrying it whever she went (to the bathroom????)...so, one day she accidentally forgot it, and...well...let's just say that what I found on it still haunts me to this day... Her ex that broke up with her was flooding her inbox with "Goodnight babe, I miss your kisses" and all kinds of things like that...I was flabberghasted and hurt to say the least...