Let me say this.... All suffering happens as our mind engages in the future or the past. This is impossible when fully in the now. Think about this. All comparisons or fantasy scenarious require placing awareness in the past or the future. Play with this notion.
Let me explore some random comments..
"I also fear that I feel too much, or too deeply. Walking through the mist of life with a hanging and heavy head is much to endure, and arises purely because of feelings for another, another I have never even met I hasten to add! "
What you describe here is classic apathy. Imagine if you filtered the exact same experience from a place of courage or peace. Very different experience. Also bring in the aspect of not suffering in the Now that I previously mentioned.
This is "state" changing ;-) Life altering. It steers consciousness very differently.
Forgiveness and compassion may be in order to understand and accept why she would feel inclined to spend time with someone else in my absence."
You said in an earlier post that you pulled away for a few months. Was this a formal break? How was this break communicated?
I say this from a centered place. I sense some lack of self love issues that may be mirrored back to you in relationships. There seems also to be huge fear surrounding potential partnership along with worrying about potentental loss. Lots of what if's seem te be harbouring your mind?
Also thinking in rewards is a set up for disaster. There is ONE reward. The 'reward' is the ongoing experience of what is happeing NOW! The ongoing experience that takes place in the now IS the reward. Perhaps a more empowering vantage point is to enjoy the journey in all its variance. When we live for rewards (future events) we miss the journey (always happening in the now). If you see the power in this, it is truely a revelation and a VERY spiritual distinction.
Self fulfiling prophecies come about by negatively filtering and charging a benevolant situation. Then we begin to create the reality that matches our emotionally charged filtered thought forms. ;-)
Are there any patterns you observe in her that make you leery?