Welcome!
I relate well to your struggle.
Simply signing up for "the 90-day thing" probably won't be enough.
Beating this addiction takes a little more work than that. A new approach. I admire your commitment. Direct your efforts in the best possible way by reading the basic materials referenced above. Simply fighting the urges doesn't work. Otherwise none of us would be here.
Here's a way to jumpstart your recovery:
1) Bulletproof shmiras eynayim. No women. No part of them. Not live and not in print. Not tznius and not otherwise.
2) Guard your mind against sexual thoughts and images. When these come, start davening. You can borrow this tefila, based on steps 1-3 and 11 of the 12 steps:
"Ribbono Shel Olam, I am powerless over lust and my life has become unmanageable.
Only you can restore me to sanity.
I turn my life and my lust over to your care and ask you to please heal me from this illness of lust. I don't want to lust, I only want You and a relationship with You and Your Torah, (and appropriate attraction to my wife). Take my lust. Please, take my lust"
Your goal is to stop
lusting. In addition, the Pesach seder is a unique, once-a-year opportunity to get out of enslavement to any Y"H. Take a look at this post for specifics on how to do it:
www.guardyoureyes.org/forum/index.php?topic=3750.0 And finally, because I know you're just so curious, here are the famous 12 Steps that have helped so many millions of addicts of every sort break free and start living real again (I resisted working them for a long time. Now I'm a fan.) :
Step 1 - We admitted we were powerless over our addiction - that our lives had become unmanageable
Step 2 - Came to believe that a Power greater than ourselves could restore us to sanity
Step 3 - Made a decision to turn our will and our lives over to the care of God as we understood God
Step 4 - Made a searching and fearless moral inventory of ourselves
Step 5 - Admitted to God, to ourselves and to another human being the exact nature of our wrongs
Step 6 - Were entirely ready to have God remove all these defects of character
Step 7 - Humbly asked God to remove our shortcomings
Step 8 - Made a list of all persons we had harmed, and became willing to make amends to them all
Step 9 - Made direct amends to such people wherever possible, except when to do so would injure them or others
Step 10 - Continued to take personal inventory and when we were wrong promptly admitted it
Step 11 - Sought through prayer and meditation to improve our conscious contact with God as we understood God, praying only for knowledge of God's will for us and the power to carry that out
Step 12 - Having had a spiritual awakening as the result of these steps, we tried to carry this message to other addicts, and to practice these principles in all our affairs
Now you're cookin'!