Fear of abandonment is irrational, at least in its magnitude, as it typically presents.
Reassurance by those we fear will abandon us is also pointless, because it has a limited shelf-life. Every time I ask for further reassurance, I'm basically saying I retrospectively doubt the last reassurance I received. It’s quite irrational, as I'm therefore looking for reassurance from someone I do not ultimately trust, knowing that whatever they say I will doubt in a just a few days’ or a few hours’ time.
Doesn’t really make sense, does it?
There is no point in 'working on' this (or any other) fear. That really implies I intend to retain it but mitigate its consequences or transform it into a more benign form, somehow.
The truth of abandonment: everyone will ultimately abandon me or I will abandon them, either dead or alive. That’s the way the cookie crumbles.
If I want relationships on any level of any significance, I'm going to have to deal with the fact that, if I get attached, I'm going to feel pain ~when~ that person leaves my life, unless I have the misfortune to die first. That pain will sometimes be protracted and profound.
The problem is really not fear but resistance to perfectly legitimate pain.
The problem is really wanting the goodies but not wanting to pay the price, which is an essentially childish attitude.
As adults with a twelve-step programme and therefore access to God and endless others who can act as channels for God's love, with an attitude of usefulness, cheerfulness, and kindness, we will never be more alone than necessary, and the inevitable (sometimes protracted, sometimes profound) pain is a perfectly acceptable and normal occurrence we will be able to handle with courage and good humour.
The other, more sinister aspect of a fear of abandonment is the conclusion we draw about ourselves from the fact of someone else leaving our lives. Someone leaves, and we conclude we're bad. We idiotically peg our worth based not on the understanding of our ultimate infinite worth as children of God or even a sound assessment of our conduct over our lives as a whole but on the interpretation of an individual act of another person we have apparently selected at random from the plethora of individuals who cross our paths.
What we fear then is not abandonment and subsequent solitude but the loss of the handy external fake barometer for our value as humans. We use others' so-called approval (which is usually more a statement that we are useful to them as reciprocating ego-fondlers than an assessment of our actual worth) as a short-acting painkiller to avoid facing the underlying fallacy of a person's value being measurable and anything other than infinite.
Not quite so noble, that aspect.
Fear of abandonment is not to be tolerated: it must be replaced with certain faith that God, working through our spirit and others in our lives, will see us through the inevitable hardships ahead provided we stay close to Him and perform His work well, plus an assertion of our infinite value merely because we exist.
Now, what instead can we do for others?