Yea, the Soviets could not afford to simultaneously hold down Eastern Europe, directly occupy China, have some semblance of a domestic economy, maintain parity with NATO on the ground in Europe, fund the R&D necessary to keep the nuclear stalemate going, and run a space program.
I figure they don't make it out of the Brezhnev-era economic stagnation intact. At least one of the following occurs: organized Chinese/Eastern European revolt spawning additional revolt in Eastern Europe/China, conventional/limited nuclear war with NATO results in loss of Eastern Europe, China revolts with US/Japanese/Taiwanese/South Korean/Australian help, USSR suffers total economic collapse and breaks apart as in OTL, doomsday scenario in which Soviet leadership succumbs to seige mentality and all-out nuclear war ensues.
My personal favorite for this scenario is a combination of 1, 2, and 4, with 2 probably featuring limited tactical nuclear weapons use.
Regular revolts in China eventually spawn limited revolts in Eastern Europe in 1977, to which the USSR wildly overreacts, putting them down with brutal and well-publicized force. NATO and the US, at this point maintaining superiority in conventional forces both in Europe and East Asia, justify intervention on humanitarian grounds and declare war to liberate Eastern Europe, while semi-openly shipping vast numbers of arms to China via Japan, Thailand, Pakistan, and India. The Soviets, having used nuclear weapons in the tactical role in China before, use them to destroy concentrations of Chinese rebels, hoping this won't provoke the West. It does, and tactical nuclear weapons are used in Europe by both sides on troop concentrations. This use favors NATO by a large margin due to its significantly more advanced mobile launch platforms. (Western R&D efforts have long since decisively surpassed their underfunded Soviet counterparts) The Soviet Navy is kicked up one side of the ocean and back down the other, simply because its submarines are older, more primitive, and above all, louder than those of the West.
By war's end, NATO forces in conjunction with East European rebels have driven the Soviets virtually back into their own borders; moving further risks provoking an all-out nuclear war, so they stop in place. China is in complete and total chaos; though the Chinese cannot win outright, they can bankrupt the Soviet Union, and the war has nearly done so already. The Soviet economy is on the verge of collapse, having lost its "allies" in Eastern Europe and forced to spend huge sums rebuilding its army to fight in China. Additionally, an upsurge of Islamic terrorism in Central Asia and the Caucasus damages oil infrastructure there, cutting off the flow of hard currency even after the war ends.
The Soviets collapse about three years after the treaty with NATO is signed, in late 1980. The Baltic republics, Moldova, and the Ukraine join NATO, while Georgia makes preparations to do so. China comes out of the revolt with a western-aligned nationalist government and begins talks with Taiwan to reunify China, which occurs in 1983. North Korea withdraws into itself; following massive famines in the late 1980's, it briefly invades South Korea in 1991 and loses the resultant war, thus allowing Korea to reunify in 1994. Russia itself is perpetually on the brink of civil war as a Communist Party successor and a neo-fascist party bicker over leadership and the spoils of a shattered economy. The northern Caucasus is in a state of near constant revolt against authority, while much of eastern Russia is considering breaking away from the west to escape the political turmoil and in the hope of actually seeing some of the revenue from the oil drilled from beneath their lands.