Nope.  I do think it forbids them from dissolving or substantially burdening a couple’s already-recognized marriage without that couple’s consent, if the states don’t jump through a whole bunch of strict procedural hoops beforehand.
For those of you who aren’t wholly fluent in constitutional law and are, improbably, still reading this thread, let me offer an encapsulated take on the difference between procedural and substantive due process as articulated by the courts.  Dewey, Poly, Hamlet, and Bricker, et al., feel free to correct or amplify my explanation.
The Fifth Amendment states in part that “no person . . . shall be deprived of life, liberty, or property without due process of law.”  The Fourteenth Amendment extends this edict to the states.
The first tricky bit here is figuring out whether something constitutes life, liberty, or property.  Slaves are property, per Dred Scott; being able to raise your child your own way is a protected liberty, per Santosky; being able to enter into a contract with a consenting individual is also a protected liberty, as Lochner, for example, acknowledges.
Two important points here:
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There is virtually unanimous agreement that something need not be explicitly mentioned in the constitutional text in order to be classified as a life, liberty, or property interest.  That is, the Constitution doesn’t say, “The following things shall be considered liberty interests…”  It is necessarily left to the courts and the legislatures to so infer.  “Liberty” could fairly easily be restricted to, literally, a person’s liberty – whether or not an individual is being bodily confined by the government.  “Life” and “property” could be given similarly narrow readings.  This has not, interpretatively, been remotely the case. 
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The analysis of whether something is a life, liberty, or property interest is the same for both procedural and substantive due process.  This is why Dewey confused me by saying, “Sure, Santosky says something about a fundamental liberty interest, but it’s really concerning itself with procedural due process.”  Whether something is a liberty interest is a necessary part of whether procedural process is due. 
Now.  Once something has been characterized as a life, liberty, or property interest (“the Interest”), the difference between procedural and substantive due process is (to my view) as follows:
Procedural due process states that the government may not deprive someone of the Interest at issue without jumping through procedural hoops to do so.  The more fundamental the Interest, the more stringent the nature of the procedural hoops – at its strictest, due process demands “fundamentally fair” procedures, a term that incorporates, among other things, “the opportunity to be heard at a meaningful time and in a meaningful manner,” Mathews v. Eldridge, 424 U.S. 319, 333 (1976), and the “opportunity to confront and cross-examine adverse witnesses.”  Goldberg v. Kelly, 395 U.S. 254, 269 (1970), although the analysis of what procedures are fair “is flexible and calls for such procedural protections as the particular situation demands.”  Eldridge, 424 U.S. at 334.  If fundamentally fair procedure has been afforded an individual, the government may deprive that individual of a fundamental life, liberty, or property interest.
Substantive due process, by contrast, states that there are some life/liberty/property interests that are so fundamental that no procedure, however fair, justifies their deprivation in certain circumstances.  So where procedural due process says “the government can deprive me of Interest A if first provides me with fundamentally fair procedure,” substantive due process says, “the government cannot act broadly to deprive me of Interest A.”  This is not to say that the government can’t regulate and limit Interest A – the liberty to contract still exists, even post-Lochner and West Coast Hotel, but it’s never been the case that such a liberty prevents the government from criminalizing prostitution or drug trafficking or the sale of children.
As can be seen, the line between procedural and substantive due process, regarding deprivation of a recognized life, liberty, or property interest, can be altogether blurry.
Is that about right, guys?  (I’m assuming that Dewey and Bricker will take issue with that last sentence there…)