Yes, that's quite right.
Sitting in convention, to amend the Constitution of the United States, in Article IV of which is where the problem lies.
There is no "problem" with Article IV.
Article IV Section 1. Full Faith and Credit shall be given in each State to the public Acts, Records, and judicial Proceedings of every other State; And the Congress may by general Laws prescribe the Manner in which such Acts, Records and Proceedings shall be proved, and the Effect thereof.
I've provided ample case law to prove that the Full Faith and Credit Clause is not absolute in the case of marriages, hell, it isn't absolute in the case of gun permits, the ability to practice law, medicine, etc.
You have yet to provide with any proof that Congress would in fact enact the actual Amendment that you believe should be enacted, or that Congress can in fact "fix" this problem any better than they've handled any of the other myriad issues they've attempted to "solve".
If the people of the State of Massachusetts decide that they don't have a problem with same sex marriages, that's THEIR decision, let them make that decision at the polls next election.
Your solution actually comes down to using the force of the Federal government to remove the ability of the States to make that choice.
The Constitution says that each individual State gets to decide, I stand with the Constitution, and I want Florida to decide what Florida should do, not for this issue to be decided by the Feds and special interest lobbyists.