Need advice parenting teenage step-daughter
Back Story:
Met my DW four years ago and dated a few years before we married. Both of us had just gotten out of a 10 year marriage. Mine ended up with EW cheating. DW's marriage ended due to major BD drug issues.
SD13 is definately a "Daddy's Girl" but has not been engaged with BD for several years. BD is a talented musician who threw his talent away on drugs (meth and pills). SD13 is aware of this and has major anger and bonding issues.
SD13 is a smart,talented, beautiful girl who is well matured (physically and somewhat mentally) for her age.
We have had a hard time bonding. She can be abrasive, part of her personality I suppose. I try to spoil her rotten (which she doesn't mind and rarely thanks me) and at the same time joke around and light banter (which she doesn't take kindley and becomes emotional no matter how innocent).
I get the "daddy issues" thing and I respect that and don't try to force the relationship. I just try to ommunicate that I love her and am there for her of she ever needs me.
Now to the issue:
SD13 with actually be 13 in a month. She has been on an emotional rollercoster with her horemones. It has afected her school and friendships. She has turned (as I like to call it) to the "Dark Side". She likes to wear black and like to listen to Emo-Rock. But God forbid you refence EMO or GOTH. She "IS NOT" that..so she says. She has admitted to cutting and thinks about suicide. (We have her in therapy for this)
She has met an older "rocker" boy (Age 14) and he is HER WORLD.
We are a technology proactive household. SD13 has had her Facebook page since she was 9. She has a smartphone and uses Skype (video conference) to talk with her friends.
In the past year I would run across foul language on her friend's post and decided to take a furthur look. At ages 11 and 12 such language is not acceptable so I took steps to block, filter this type of behaviour.
I decided to take it a step further and install monitoring software on both phone and computer that would pick up on such behaviour and language. For the most part it is innocent...but now that she has this boyfriend...all she wants to do is Skype him and picked up on some inappropriate conversations.
We randomly screen calls, chats, text and video conferences. DW seems to think this is too much. She refuses to listen/read the conversation as she thinks they are intrusive. I have discovered that SD13 is still cutting and is now having "deeper" conversations with Boyfriend that or flirting on the edge of sexual.
DW and I had a blowout this evening because she thinks I am being too strict and I think she is being naive and SD13.
My instinct is to trust SD13, but after reading/listening to converstation, I am not so sure that I trust either one.
Needed to vent. Sleeping on couch tonight. 
Keep venting! Kids will get
Keep venting!
Kids will get away with as much as you allow them to. Good job on the monitoring software. We (DH and I) are a bit beyond that point. We might would install it if we ever had SD16 in our house for longer than a couple weeks at a time, but we don't.
I'm honestly at the point of starting to let SD16 spread her wings within reason. Both her father and I got up to shenanigans at her age (sex, cigarettes, drinking, evading the cops after curfew) but we never got caught. She does. Honestly, I wish she'd learn to sneak better.
But at 13, you're doing the right thing. Your DW needs to get her head out of the sand - this is not her adorable 3yo who ran to Mama for every booboo and thought that Mama put the sun in the sky. This is a teenager. Keep up with what you're doing. Make recordings. She has pretty much zero rights, but your DW needs to buy in.
It sounds as if she may have
It sounds as if she may have gotten too much freedom (fb at 9?!) too early and now you are trying to pull back the reigns. Not that you're wrong, but it may have gone too far before you realized it. Kids have to be 13 to get fb for a reason. Mainly it's because there are other 13 year olds on there posting HIGHLY inappropriate crap...pics and language. Then there are the hacks where they are exposed to blatant sexual images. Anyway...
My dd9 is EXACTLY.LIKE.YOUR SD13. Right down to her relationship with her bd. He is daddy's girl, but he is inconsistent at best and continually lets her down. I see her being in the same spot as your sd one day. The way I have always handled anything is with honesty and love. Your sd is looking for the love she has not received from her bd. Hormones just make it worse. My parents are still married and my dad came home everyday after work, but he was emotionally unavailable and hardly ever spoke to us kids. Not bonding with a father figure positively can have serious effects in the teen and even 20s, or until the girl figures out what's going on. We tend to latch on too easily and give too much, hoping to get the love we never got growing up. Have a sit down with her and just talk frankly. Tell her what you are seeing and why it's bothering you. She will see that you care. Don't come at it in a punishing sort of way, but out of concern. Have the boy at your house for dinners.
It is ironic that at the time when our children need us the most, they push us away and we figure they are "grown" and oblige. But puberty and adolescence is when they need us to reign them in and keep them close, to protect them from their own stupid decisions and take the peer pressure off of them. As they scream "go away" what they really want is help with what they are dealing with because it is overwhelming. Of course, they don't realize this until much later on, when they are grateful for that mom or dad that did hang on despite the resistance. Hang on with everything, even if bm doesn't. Mom/daughter relationships are WAY different. Women can be stupid LOL. Why do you think so many people here have psycho bms?!
You should read the book Step
You should read the book Step Monsters. It helped me realize many things. It doesnt matter what you do or dont do for this young lady. You will never be somebody she will respect. Even if you think you are. Read the book it will help you to realize that every situation is different BUT the outcome is pretty much the same. I'm sorry you are dealing with such an angry upset child. I wish you luck.