As someone who has had major sleep issues at different chapters, I can relate.
One of the primary drivers is the neurosis/anxiety that you've likely developed in anticipation of sleep; it was for me. The way I dealt with it was with the following tools (beyond what other people have mentioned)-
If you're married, try sleeping alone for a week to see if it takes some pressure off of you to not disturb your partner. If it works, it proves that you can sleep, which is a big step to breaking the neurosis.
Also, the best thing I did to break my worst insomnia stint was to do meditation and/or yin yoga. Google yin. It's basically giving yourself permission to stop thinking and slow down. As westerners, we're not very good at separating our day from our night.
Good luck, I know it sucks.