According to Rambam - Let the Pervert Die!

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http://www.chabad.org/library/article_cdo/aid/904980/jewish/Yesodei-haTorah-Chapter-Five.htm
Rambam, Hilchot Yesode Hatorah Chapter 5
Halacha 9

[When] someone becomes attracted to a woman and is [love-]sick [to the extent that] he is in danger of dying, [although] the physicians say he has no remedy except engaging in sexual relations with her, he should be allowed to die rather than engage in sexual relations with her. [This applies] even if she is unmarried.

He is even not to be given instructions to speak to her [in private] behind a fence. Rather, he should die rather than be given instructions to speak to her behind a fence. [These restrictions were instituted] so that Jewish women would not be regarded capriciously, and [to prevent] these matters from [ultimately] leading to promiscuity.

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Rambam's source according to Kesef Mishna is the Talmud Sanhedrin, page 75a.
There the Talmud brings a debate is this halacha applicable only when the woman is married or even if she is single. Rambam rules even when the woman is single.
The Talmud in Sanhedrin 75a also states there explicitly, that we don't save this guy, even if he only wants to look at her without clothing, without actually touching her. And then ends off with an even more extreme statement, namely, what the Rambam quoted that we say let the guy die even if he only wants to talk with her behind a fence.