If she refused to go he would simply leave her; yes, he was just the man, the wild man, to do precisely that disgraceful thing.

And she would be horribly afraid to spend the night alone in those woods with only the guides and Selina, not to speak of facing the morrow--for he might refuse to take her back! Where would she turn in that case?
What would her grandmother say?
Who would support her in making such a scandal and giving up a husband for reasons that could not be made impressive in words though they were the best of all reasons in terms of feeling?
No, if she gave him up she would be absolutely alone, condemned on every hand, in the worst possible position.

Then, too, the break was unattractive for another reason.

Though she despised herself for her weakness, she did not wish to give up the man who had given her that brief glimpse of happiness she had dreamed as one dreams an impossibility.

Did not wish?
Could not--would not--give him up.