As Tsuyoshi points out in a comment below, there is no reason why a solution to the problem has to be a stable matching. So, the approach of this answer does probably not work; especially since I believe that Tomer's answer is correct.
It seems that your version of the Marriage problem is equivalent to the Minimum regret Stable Marriage problem with Ties, where everybody ranks the members of the other sex with possible ties, and the goal is to maximize the minimum "happiness".
It is shown in [1] that Minimum regret Stable Marriage problem with Ties is not approximable within $N^{1-\epsilon}$, for any $\epsilon > 0$, unless P=NP, where $N$ is the number of men in a given instance of the problem,
even if the ties are on one side only, there is at most one tie per list, and each tie is of
length 2.
[1]: David Manlove, Robert W. Irving, Kazuo Iwama, Shuichi Miyazaki, Yasufumi Morita: Hard variants of stable marriage. Theor. Comput. Sci. 276(1-2): 261-279 (2002). Postprint.