A difficulty often met by the buddhist practitioner is in judging yourself harshly for not being "detached enough" at times…
After the post gplus.wallez.name/fJcgmKdWTV5 on marriage as an opportunity to practice , let's explore separation as an opportunity to practice!
The difficulty to deal with loss usually is at its worst with regards to inter-personal relationships: losing a friend or a lover, feeling betrayed or abandoned… The pain may sting deep by itself, but you may add to it by beating yourself up for not being 'buddhist' enough: not accepting impermanence enough, not accepting selflessness enough, not accepting pain enough… At this juncture, you 'know' it's a form of ignorance but all you would want is for the relationship to last a bit longer, for you to be intrinsically separable from this ball of pain, for aversion (to suffering) to be seen as freedom (and not as merely an automatic reaction)…
There is no cessation of suffering, if there's no suffering to cease.
For all the pain you might experience, there lie lessons!
Losing someone dear —in particular when it is out of choice by the person leaving— holds great lessons in selflessness.
It feels like you continue carrying the other around in your head, in your heart… even though this person had changed —since (s)he left— and continues to change! While what's in your head feels 'true', it is quite obviously a mental fabrication based on a past and very loosely tied to any present reality…
Just like you freeze others in (semi-)permanent views on who they are, you freeze your own image of who you are. All these views miss the contingency of life though.
Just like selflessness did not prevent the Buddha from referring to himself as a person, your selflessness does not make you vanish. You may have identified as "the lover of…" or "the friend of…", and losing this identification may create a lot of anguish, but you will not just disappear! It only was a self-proclaimed identification: you don't exist as you imagine you do — this is selflessness, you cannot pin down a 'self'.
It may feel like you cannot live without the other… except you do live, right here right now. Impermanence is how life manifests, permanence is unborn!
If you feel you cannot live under such a pain, you may be confusing inter-dependence at large with a mental misrepresentation of it: you are inter-dependent with what existed and what exists now, but you are not vanishing if a phenomena you previously appropriated now ceases!
What causally participated in creating who you are now doesn't vanish from the past simply by taking an unexpected turn in the present… What you influenced in the past will continue feeling this influence even while walking away… Inter-dependence still applies, causality still applies.
Simply, causality and inter-dependence are not bonds you can use to 'secure' yourself to something: causality is actually how impermanence manifests (if a cause has a consequence, it's because its object could be changed i.e. was not permanent; otherwise no consequence is possible)!
Inter-dependence is about how you use the context (in a relationship / not in a relationship) to illogically define who you are ("I am a good friend" / "I am unjustly abandoned"…).
There are innumerable lessons in the experience of suffering. The cessation of suffering requires you to enquire into your pain in order to understand it, to understand the fear of vanishing when losing your certainties, etc.
Karma is tendencies.
The ignorant and natural condition is to perpetuate the pain, to cling to "what was" as representing "what has to be", even though it may have been good for you at a time (at best) but not necessarily so any longer…
The tendency to think that something retains its pleasantness, even when this later contradicts the experience, is karma. As it is an ignorant view projecting permanence, it is karma leading to rebirth (the next moment or next life) into a world of suffering.
Knowing how to say good bye ("It was nice! See you when I see you" —no lust, no aversion) is a deep lesson. It's hard to learn, but every separation is an opportunity to practice.
The ignorant and natural condition is to cling to what was perceived as a solution to existential anxiety… even when it just proved not to be a solution at all, and even though it never could have been a lasting solution!
This perpetuation of belief in an external solution to an internal existential anguish is saṃsāra. To realise that you don't vanish when it feels like you loose ground is a deep lesson. It's hard to learn, but each loss of certainty is an opportunity to practice.
Meanwhile, "creatively engaging" with the pain might lead to create a great guitar solo (8'37'' video "Don't go" with Ulco Bed (guitar) playing with Candy Dulfer at Leverkusen Jazztage (2009): Candy Dulfer - Don't Go Amsterdam HQ ).
If the pain is there, "see things as they are" i.e. don't wish it away! Fact is you're not enlightened yet? So be it, don't beat yourself for this! Use causality: transform the pain in insights, in art, in understanding and compassion for the difficulties of others…
Easier said than done? Sure! If it was easy to become Enlightened, you wouldn't need to produce "right effort"! But if you don't even try, and try again, to drop your tendencies and become free to choose, free to say goodbye? Nirvāṇa is unconditioned, but the tearing of veils and the removal of hindrances is dependent on your efforts… So you work through it, at the pace you can; that's the Path.