Philippe Cottet explains Girard's theory as denying individuals any autonomy in matters of desire:

By analyzing the novelistic masterpieces (Cervantes, Stendhal, Proust and Dostoïevski), René Girard reveals a different mechanism for . . .  human desire. [It] . . . [does] not fix itself in an autonomous way according to a linear path between the subject and an object, but by imitation of the desire of an Other, according to a triangular plan: subject - model - object. . . .  Girard's hypothesis rests on the existence of a third element, [the] mediator of the desire, who is the Other [or model]. . . .   [O]nly because the man I [take] as a model is desiring or is in possession of an object (conceived in a broad meaning as any thing with which the other seems gratified and which is lacking to me...) [do] I begin to desire [that object].  The object has some value only because it is desired [or possessed] by another. . . .

The desire that the subject has for the object is nothing else but the desire he has for the prestige that he attributes to the one who possesses the object (or who [begins to] desire the object at the same time as him). . . .

The model has no passive role in this triangle. . . .  As an object for which nobody would compete . . .  would have no interest, no value able to fix his own desire, everything urges him to [advertise] his good fortune - which [is just that] only if it is recognized as such by . . . others.  To be [fully realized], the [model's] desire . . . needs to feel the . . . [mimetic] desire [of others].  It thus tends always itself to arouse competition, i.e. to cause the emergence of a rival . . .

When the student has same knowledge as the Master, there is naturally . . . no more student or master, but two people having the same knowledge: the initial hierarchy . . . is abolished. The model feels the danger that this confusion can present for him, this indifferentiation. . . .  [T]he more the mimetic rivals . . . try to be different,         . . . the more they end up resembling each other.

The question of the loss of the differences is central in the Girard's hypothesis. . . .  [H]uman cultures are founded on the permanent creation of differences which [allow people to classify] things. The archetypal sentence "[M]an is the only animal who knows that he will die " is a very good illustration. . . . Our need [to comprehend and organize] the world is realized thanks to this permanent creation of differences. . . .  In fact, we live and think in a system essentially differentialist. A certain positive thought, moreover, considers that sense [or meaning can] arise only from a situation of imbalance between two [different] terms, and this [perception] urges us always to look at what separates [things] in order to understand [a given phenomenon].  [Faced with two] identical [things] , we immediately try to distinguish, [as is evident in people's response to] twins: most of the time, we try to find at least one characteristic in one or the other . . . [that will] allow us to know who is who.

[M]imetic desire [tends to obscure] these differences, [and thus to confuse] all the preexistent reference marks. If nothing of what distinguished me from my neighbor exists any more, who am I really?

The [closer] they are [to one another], the more the rivals [resemble one another]. As Girard [puts] it, " the mimetic triangle is isosceles," model and subject occupying in turn the role of the mediator. What we have just described concerning the subject affects also the model.  The hatred [that] rises from this conflict is [latent with] reciprocal violence.

It is also helpful to note that, according to Girard, mimetic desire has very clear homosocial underpinnings.  Here's a good account of the theory of "homosocial desire" as it is defined in Between Men: English Literature and Male Homosocial Desire by Eve Kosofsky Sedgwick:

In Between Men, Eve Sedgwick defines "homosocial desire," a term borrowed from the social sciences, as a continuum along which one may describe the social bonds among either men or women. The concept of homosocial desire alludes linguistically to homosexual practices, but Sedgwick warns that it should not be thought of as synonymous with them; homosexual behavior is but one position along the continuum of social practices that a theory of homosocial desire seeks to situate. Desire is seen in this context as a social force rather than an expression of singularly physical wants. Male homosocial desire, then, is a measure of male bonding practices and a method of emphasizing the structure of men's relations in a patriarchal system. As Sedgwick notes, the maintenance of a patriarchy is dependent upon heterosexuality; it is not, however, dependent upon heterosexism (or what we commonly call homophobia), as her example of early Grecian society shows. Both patriarchy and heterosexuality are based in what Gayle Rubin calls "the traffic in women." From this viewpoint, women are seen as exchangeable property for the cementing of bonds between the men who "possess" them. All this leads to what is Sedgwick's central idea in Between Men: that heterosexual relations are strategies of homosocial desire. That is, heterosexual relations exist to create, ultimately, bonds between men; such bonds, she furthers, are not detrimental to a concept of masculinity but actually definitive of it (50). Sedgwick identifies the strategies of homosocial desire as "erotic triangles," relationships in which there is rivalry between two active members (often, but not exclusively, two males) for the attentions and/or affections of a "beloved" third.

Quoted from Matthew Henry,
"Erotic Triangles: Homosocial Desire in Double Indemnity"
http://www.rlc.dcccd.edu/annex/comm/english/mah8420/EroticTriangles.htm