Its only recently that I’ve heard people talking about finding their twin flame.

I googled it and from what I read finding your ‘twin flame’ does not necessary mean living together in a committed relationship. In fact it kind of points to the opposite. A experience that’s can only last for a short time before it burns it self out and becomes something else.  A relationship intended to fire you up but not a place you can live in.

As a metaphor ‘twin flame’ is problematic as I invasion the ‘burning of the candle’ at both ends. Fire consumes oxygen making it hard to breathe. Fire burns, love burns… and when out of control burns everything in its path. But fire also purifies and creates the ground for new things to grow… I don’t know… One must be careful when playing with fire

You ask if this is an illusion.

• The angst your experiencing is not a illusions.
• The idea of a ‘Twin Flame’ soul mate are words and words are symbols not the thing itself and so a illusion.
• If you expect this relationship to move forward into a more committed one… that may be an illusion. As a guy having a friend with benefits, having my cake and eat it to… yeah I’m going to keep that going as long a possible (if I were the type of guy that would enter into a friends with benefits relationship – My observations is that they seldom end well)

I don’t know your making yourself crazy by becoming engulfed by the experience and getting burned so maybe the twin flame is a real thing.  Its just not how I’d like my relationship to look like.  Your Friend wants his X back, but you want something more… My opinion for what its worth tell him no more benefits and see how long the flame burns true.