Why does Darnay travel between france and england and when is it told in the book

Darnay has traveled back and forth between France and England, building himself a business and refuge. He sees what is about to happen in France and wishes to distance himself from his family and their actions. He believes in the cause, and the end of oppression, but he does not support the bloodshed so near in the future.

“"If it ever becomes mine, it shall be put into some hands better qualified to free it slowly (if such a thing is possible) from the weight that drags it down, so that the miserable people who cannot leave it and who have been long wrung to the last point of endurance, may, in another generation, suffer less; but it is not for me. There is a curse on it, and on all this land.”" (Page 109)

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"“I have already said, that for my prospering there, I am sensible I may be indebted to you, sir. For the rest, it is my Refuge." (Page 110)