Welcome back.
Boy have I been where you are. I agree. Giving in to lust ruins our chances of true intimacy. But I wouldn't say you've ruined it forever. Just like you haven't ruined yourself forever. As addicts we either ruin ourselves every day or recover every day.
There are two basic steps to recovering from this addiction. The first is getting sober. The second is repairing the damage.
To get sober from a drinking problem is simple. Stop drinking and you're sober. One light beer, one spoonful of cough syrup in alcohol and you're back to square one.
To get sober from lust addiction it's the same. Just it's trickier because there are so many ways we get the lust drug. It's basically divided into what we see and what we think. So to stop lusting, we must first commit to guarding our eyes in all settings. No women. No part of them. Not live and not in pics. Not on television nor in movies or youtube videos. Not in advertisements anywhere. Not their faces and not their shoes. The stricter you are the easier it is. If you need to look for business, keep it to a minimum. I pinch my inner thigh hard whenever I catch myself glancing at a woman.
For the fantasies, which were a major challenge for me personally, I have had success applying the first 3 of the 12 steps. I've turned them into a tefilla, and I say it whenever I detect a lustful thought. Ideally, I try to deflect the thoughts very early. If the thoughts come when my eyes are closed, I open them and look around. I will say this tefilla over and over until the nisayon has passed. This will require much repetition in the beginning and will be a monster struggle.
But the struggle isn't against lust. It's the struggle to step aside, to avoid it, and to let Hashem take it. Here's the tefilla:
Ribono 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. I surrender my lust to you. Please take my lust.
Look through the 12 steps and begin to understand and work them. There are many other tools here on GYE. If they work for you, great. If you make an honest attempt to give up lust and just keep falling, consider joining a local SA (sexaholics anonymous) group. They work. Many here who haven't had success doing this on their own have found recovery through SA.
Break the challenge down into one day at a time. You just have to get through today. One day. Just today. You can do that.
Hatzlocha,
Alex