Sentence:  Of the two ways of making love, adultery must seem the safer, as the <WSD>aerialist</WSD> engaged in it swings to an eventual stop, or else lands in marriage itself which is strung out protectively under the highwire. Whereas a man failing in marriage has nothing to break the tumble. 
Meaning of the word marked with <WSD> tags:  An acrobat performing high off the ground, defying a fall to earth, as on a trapeze or a tightrope.