What is the central idea in "The Girls in Their Summer Dresses" by Irwin Shaw?

In Irwin Shaw's "The Girls in Their Summer Dresses," the
central idea I see is that relationships are fragile, especially when the people
involved are not deeply committed.

Michael Loomis and his
wife Frances are walking in New York City, and it is obvious that Frances wants to have
a day that revolves around Michael and no one else. She mentions that they are always
with others:

readability="7">

"Let's not see anybody all day," Frances said.
"Let's just hang around with each other. You and me. We're always up to our neck in
people..."

While this might
seem to suggest a devotion to her husband, it may simply be a tactic to be close to a
man she does not feel "safe" with: she feels insecure in that he is not completely
vested in her; but it is hard to say whether or not he is committed
to the marriage—the conflict arises because Michael constantly watches other women. When
Frances calls him out on it, his responses may simply be the result of his annoyance
with his wife due to her accusations; he may be responding with sarcasm—or he may be
choosing to open up to his wife—but not in a constructive way. Michael's childish need
to satisfy his own pleasure in watching other women does not allow for his wife's
unhappiness over it. Frances, however, needs too much reassurance to give the reader the
sense that theirs is a happy marriage. He pulls away, she pulls him back,
closer.

For the relationship between the two to be truly
functional and happy, Michael should be mature enough to watch women on his own time,
not when his wife is with him—it shows a lack of regard for her feelings and a
deep-seated dedication to satisfying his own needs over those of the woman he is
supposed to "love, honor and cherish." Michael takes no
responsibility for what he does, blithely dismissing his actions—he won't take a stand
as to whether it's right or wrong, which probably says it
all:

"I look
at women," he said. "Correct. I don't say it's wrong or right, I look at them. If I pass
them on the street and I don't look at them, I'm fooling you, I'm fooling
myself."

Part of the problem
may rest with Frances, but only because her desperation might drive someone as shallow
as Michael away—this sign of weakness would more likely make him
resent her. While he seems sympathetic about the pain the topic
(and concept) brings her, rather than showing her the attention and regard she yearns
for, he insists on explaining, in painful details, how he likes to watch other women and
that he might choose to leave her at some time—showing a lack of any real distress for
her.

"You
want them," Frances repeated without expression. "You said
that."

"Right," Michael said, being cruel now and not
caring, because she had made him expose himself. "You brought this subject up for
discussion, we will discuss it
fully."

Michael says he has
never touched another woman in five years. Frances' problem is that he
wants to. He is unhappy that she has pushed him into admitting the
truth aloud (though his behavior needs no "translation"), and she is unhappy because he
is not "exclusively" hers in her mind, and their relationship is
not progressing in a positive direction. It would seem that it
never will as the author describes Michael's behavior when Frances walks away to call
the Stevensons: even Frances, in Michael's mind, is a
sex-object.

readability="9">

She got up from the table and walked across the
room toward the telephone. Michael watched her walk, thinking, What a pretty girl, what
nice legs.