Don't think I'm as old as Squire Fulwood
but am a man but I do know a bit of what your are going through. Although my wife isn't diabetic (I am) we went through hell trying to conceive, various IVF and other fertility treatments all with varying degrees of success and ultimate failures for what seemed like for centuries. So failure to conceive is not just down to your diabetes - T0s fail more than is usually banded around/generally mentioned. And you have a better life style than most by the sounds of it and certainly amazingly good control - so well done!
That dark place you mention, we've been there and done that during our IVF years - you enter as a couple but that rollercoaster takes its toll and before you know it one partner is sat at the front and the other retreating to the back seat, also the pressure and stress involved has an adverse affect - just like if you stress over high blood glucose results they go even higher! You can't force your self to be pregnant - after five years god knows how many times you've tried! Unlike you, my wifes clock was certainly ticking nearer and nearer to the alarm, it was getting desperate - after the last failed attempt we allowed ourselves time, time to think and ponder the future with out children and to also get our lives back on track, we stopped the rollercoaster, enjoyed the peace and quiet of the tranquil picnic area, and were considering leaving the amusement park behind us - it was that that was the dark place and all that went on in there. Like a pair of silly old timers, well we had nothing to loose, we once more joined the fast-track queue for another ride. Except when we got to the turn style we didn't need too!
You can afford to take time, give yourself a break - from it all now and again, completely - you just never know what might happen in the mean time. Take time to be yourself and not some pin cushion or some odd brushless electric toothbrush type device holder (only those that know will know what I'm on about!)!
All the very best.