I can't believe you're getting on your guy's case over emotional-tampon issues..
Your bf is being her emotional-tampon.. (why? many reasons.. in order of most likely)
1. He's too much of a nice-guy and actually feels good about helping people with their emotional problems.. (makes him feel special)
2. He has poor technique and is stuck being her emotional-tampon even though he really wants to have sex with her
3. There's an issue that involves him and it directly benefits him to solve some issue
4. They've already had sex and is too wipped to not assume the role of emotional-tampon
(I know you've only focused on 2 & 4.. and I want you to think about that fact for a second.. what does that say about you? Are you the rational and composed gf who has enough trust after 6 years to not feel insecure about this issue? Or are you a George Bush that's going to push to send bombs over his way because you thought some Helium gas trucks were biological weapons?)
I want to tell you a short story.. Back in college, my favorite professor was Prof. Liveson.. we had a great relationship.. so great it actually motivated me to outpreform the rest of the class.. and the more I did, the better relationship we had (he realized I wasn't comming to his office to "suck-up" with a 99.5 average).. But one day someone suggested that students where cheating in the front desks.. so he came by and asked to see my test, calculator, and work.. Although he realized I wasn't cheating, and he even felt ashamed he doubted me (and said a genuine "sorry").. I felt insulted at his lack of trust and faith in my resolve, character, and our relationship.. After that day, he was just a professor; I never showed up to his office again.. Whatever we had, was over..
In all honestly, if there is enough trust and your faith in the other person is strong enough.. there's no need to behave this way.. it only shows him your lack of trust and faith in your relationship.. which says a lot after 6 years.. And the funny thing? The more trust/faith you show to him.. the more pressure he has to "preform" and justify it.. He will constantly think "wait, what am I doing, I have my fiance' who loves me, trusts me, and has all this faith in me, and it doesn't bother her for me to be out.. how horrible would it be of me to take all that, and throw it away?"
It's more effective to tell him.. "I just want you to know, that I found some texts on your phone, and I know it's not right to be going through your phone.. and when I saw them, they bothered me.. but.. I trust you.. I know the kind of person you really are.. and I realized I was just being irrational.. I just thought I should tell you though.." (he can't possibly take this the wrong way, you've covered all bases.. PLUS, you're painting a positive picture of him which he'll want to conform to)
It's less effective to say "Who is this girl? How come you haven't told me about her? Where were you before? Why did you write this to her? Why does she keep contacting you? Why? Who? What? Where? How? Tell me! I want you to stop talking to her, I want you to call me to tell me where you are.." (you only suggest what kind of life and bitter relationship awaits him after marriage; you're insulting his character & loyalty.. but more importantly, you're throwing away 6 years of trust because of a text message which contained none of the following "last night was amazing, I can't wait until you go down on me again, I want you inside me.. tonight, I bet your gf hasn't blown.. your mind.. that way, etc.."
I'm not telling you what to do.. you're a grown up & responsible woman.. i'm sure you can make the right choice on your own.. but just think about it..
If you can't stop the Wind, then you can't stop the Storm.