Yes. Rashi cites this in his commentary to Gen. 36:3 (explaining why the name of one of Eisav's wives is given as "Machalath" when earlier she was called Basemath; Machalath is related to mechilah, forgiveness), in the name of Aggadas Midrash Sefer Shmuel (ch. 17). (It's also in the Yerushalmi, Bikkurim 3:3.)
This is in fact one of the reasons why a bride and groom fast on their wedding day: it's like their own personal Yom Kippur. (Beis Shmuel on Shulchan Aruch, Even Ha'ezer 61:6)
The Lubavitcher Rebbe zt"l, in an analysis of these sources (and of the question why we infer this from a verse describing Eisav's marriage, of all people), explains that one way of looking at this is that it's the act of marriage itself - even without associated teshuvah - that brings about Divine forgiveness, much like Yom Kippur (according to some opinions). Further, he says, even those - including Rashi - who implicitly say that the wedding must be accompanied by teshuvah, would agree that even a thought of teshuvah counts for this purpose (thus the Midrash, Bereishis Rabbah 67:13, speaks of Eisav "considering converting," even though in the end he didn't follow through). The reason for this, he goes on to say, is because it enables the important mitzvah of p'ru ur'vu - procreation (in both the physical and spiritual senses).
So based on this, it is possible that it would apply even to sins between man and man (which, after all, Eisav was guilty of too).