Next year SCOTUS is scheduled to tackle the two issues. Orin Kerr finds parallels:

In both contexts, the debate boils down to the scope of the equality principles found in the Equal Protection Clause. In both contexts, the challengers to the status quo argue that the state can’t treat people differently in the area of fundamental rights. It’s that simple: This is about marriage/racial equality. In both contexts, the defenders defend their institutional practices as allowable and sensible societal responses to difficult social problems. And in both contexts, public opinion is split nearly 50/50, with very passionate opinions on both sides. The similarities are particularly interesting because few people have the same instinctive reaction to both cases.

But I'm one of them. I support marriage equality as passionately as I oppose affirmative action. I believe in formal civic equality of opportunity, not actual equality of results. Ilya Somin also points out that "people who oppose racial preferences in college admissions (the issue the Court will consider in Fisher v. University of Texas), while supporting gay marriage are far from unusual":

Recent polls show that about 50% of Americans support gay marriage, while many surveys indicate that some 60 to 70 percent of the public oppose racial preferences in college admissions (e.g. here and here). Even if we assume that some 80 to 90% of the 50% who do not support gay marriage also oppose affirmative action in admissions, that still means that about 15 to 20 percent of the public simultaneously opposes racial preferences and supports gay marriage.

For years, that position – the core underpinning of my book Virtually Normal – was regarded as eccentric. But the logic of equal opportunity is as solid for one as for the other. Eventually, people will see that. Some already are.