“I Said to my Wife, I have accepted a Seat in the House of Representatives and thereby have consented to my own Ruin to your Ruin and the Ruin of our Children. I give you this Warning that you may prepare your Mind for your Fate.”

hmmm, I wonder what the inside story was?

It sounds as if John Adams liked to introduce a little self-deprecating humor.

Here's the quote in context:

When I went home to my family in May, 1770, from the town meeting in Boston, which was the first I had ever attended, and where I had been chosen in my absence, without any solicitation, one of their representatives, I said to my wife, "I have accepted a seat in the House of Representatives, and thereby have consented to my own ruin, to your ruin, and to the ruin of our children. I give you this warning, that you may prepare your mind for your fate." She burst into tears, but instantly cried out in a transport of magnanimity, "Well, I am willing in this cause to run all risks with you, and be ruined with you, if you are ruined." These were times, my friend, in Boston, which tried women's souls as well as men's.