What do you call this type of relationship....apart from toxic and dangerous?

[WhoamI83]

What do you call the kind of relationship where your very existence depends on each other? When you spilt up you don’t exist as 2 single people. For example you live in a relationship you hate, your unhappy, your husband is abusive but you go back to them. Your husband also very clearly hates you also but he won’t leave you.
I’ve left this relationships by the way but it was difficult and I felt lost, no sense of self for a long time.

co-dependent?

Facing Codependence: What It Is, Where It Comes from, How It Sabotages Our Lives

Believing In Myself: Self Esteem Daily Meditations

Compassion and Self Hate: An Alternative to Despair

When the Body Says No: Understanding the Stress-Disease Connection

These might be some good books if you think co-dependency is something you've struggled with in the past and don't want a repeat in your next relationship x

Exactly what @feelingsomewhatlost said. There's lots of written about co-dependency so if you're still feeling lost and with no sense of self there's lots of advice online that would help.

Yes, co-dependent.
But not all co-dependent relationships have hatred or abuse in them. Many times it can be neediness, clinging, and love bombing.

Is it still co-dependence if it’s forced on you. I.e I didn’t go into the relationship like this but it seemed to occur. I had my own identity before him but it seems to have been lost somewhere.

To a certain extent all co-dependence is “forced” on both partners. They both lose their individual sense of self, and start becoming very dependent on the other partner to define what they like, how they feel, etc

A waste of your one short life?

This looks like a good resource for guidance on how to get back your identity.
medium.com/better-humans/the-recovering-codependents-field-guide-to-healing-from-heartbreak-b2a2bbc501e3

If one person wants their needs met or else and the other person wants to meet there needs because they are afraid is that co-dependence. The abuser needs the victims control and the victim needs the abusers love, is that dependent. I always thought my ex hated me but also was desperate for me to stay because he needed me for something.

If one person wants their needs met or else and the other person wants to meet there needs because they are afraid is that co-dependence

No, that is not co-dependence. That is an absuive coercive relationship.

Maybe look up "trauma bonding"?

A waste of your one short life?

THIS!!

Trauma bonding sounds a lot like co-dependence but more traumatic.
Does the abuser also get trauma bonded?

Have you looked up the freedom project OP? I believe it is to help people suffering from abuse in their relationships but not always physical abuse.