"What are the signs/symptoms?"

The truth hurts, but you still have to face it.

Spot the signs of unhealthy emotional dependency:

No control over your own life

Because you are emotionally dependent on someone, you leave your life decisions to them. You have no control over your own life.
Your life is reprogrammed and led by the dependee's decisions. One of the root causes may be to please the dependee to prevent the dependee from leaving.

low self-esteem

Emotionally dependent people have extremely low self-esteem(due to their circumstances) which leads to a greater need for support and affection.

you might go to great lengths to gain approval or to develop a sense of self.
Because that feeling of acceptance builds self-esteem but at the cost of a stable sense of self.

Lack of boundaries

As emotionally dependent people have low self-esteem and view themselves negatively, they naturally have a hard time setting any boundaries around them.

This is because they fear that ... people will stop liking them if they try to establish or maintain a boundary.

When they meet with something uncomfortable, they don't know how to say no. And when they get stepped all over on and become a doormat or offered any crumbs, they will just accept it.

Behavioural changes

Emotionally dependent people have noticeable changes in the way they are and act. They can duplicate the dependee's way of lifestyle to please and satisfy the dependee to convince him/her to stay with the dependent.

Denial

Even if there's a lot of evidence present, The dependant will refuse to acknowledge or admit their significant other shortcomings. The main reason? Because they can’t or don’t want to move on without the dependee.