Oh Mike, I am so sorry to hear. This disease stinks!
To suffer through a long term, debilitating illness is hard enough without relationships breaking apart.
Of course you are sad. I would be too. Even if it doesn't actually happen, just having it said out loud as a possibility is saddening.
I don't know where "BG" is, but I hope its not too far away.
She married you because she loves you. She stayed with you because she loves you.
I pray that she is reminded of why she fell in love with you to begin with and that things can get straightened out.
This is not a death sentence, at least she told you out loud that she's thinking about it - dialog is always a good sign.
You know, there are counselors who specialize in relationships involving long term illness. Perhaps you both can go, or even just you.
I hope you don't feel guilt over having been sick and depressed. Anyone living with a long term illness gets depressed. And Lyme is not your fault. its no ones fault.
Hang in there today and know that I am thinking of you and sending out a prayer for you both.