If this person is showing up in your dreams repeatedly, maybe you are subconsciously in search of closure?

What about writing (but not sending) a letter that gets out all your feelings toward this person. Afterward you could burn it, bury it, shred it or read it aloud to a counsellor or therapist if you have one.

I hope you are able to get a good rest soon, OP. Best wishes.

or maybe cbd.

This is fairly common psychological symbolism.
Is it possibly you've treated this person horribly at some point?
Is that why the "visions" are disruptive?
Commonly, people refer to karma, an equalization.
Perhaps, through the collective conscious, you realize that now it is "their time".
If this sounds like a fit, their time of retribution is at hand.
You know it, hence the dreams.
I wouldn't want to be in your shoes.

Meet them. The dreams will end and you'll find peace.

No physical addiction like with caffeine, nicotine, alcohol, etc... and you will sleep.

Maybe they didn't do anything weong and the dreams are just "disruptive" because they're currently in a relarionship.
You're a paranoid "glass is half empty" guy eh?

This is the way of an adulterous woman: She eats and wipes her mouth and says, 'I've done nothing wrong.

I’ve heard melatonin with gravol can work.
That, or NyQuil.

Limiting coffee to mornings only
Chamomile tea in the evenings
Getting enough exercise
Identifying root causes of anxiety
Making lifestyle changes to reduce stress
A diffuser with essential oils
Limiting screen time before bed
Reading a book before bed
Yin or restorative yoga
Apps like Calm or Headspace
ASMR videos on YouTube
Clean sheets
Doing things that promote a sense of safety and well-being
Releasing any people or situations that are holding you back

Cannabis --the indica variety--is ideal. Or maybe a really boring book!