I was thinking and can not think of a two state solution that did not lead to armed conflicts then and current tensions now. India-Pakistan boarder considered one of the most dangerous in the world. Israel-Palestine is a mess. Northern Ireland is where the second most British troops died since WWII.
That depends on your definition of a Two State Solution. One workable example is the resolution of the unified Italian State and the papacy. Given that most of the territory of the Papal States was conquered by Italy in 1860-61 and that Rome fell in 1870, and that there was a great deal of mutual antagonism from 1870 until the Lateran Accords settled "the Roman Question" in 1929, I think that this situation would fit the criteria. Armed conflict nearly ceased in 1861, only token resistance was offered in 1870, and that armed conflict effectively ceased at that point. Since 1929, the Lateran Accords have proved to be quite durable. They are still in place with only very minor changes. Italy got its capital in Rome, the papacy got recognition as a nation, and the intervening years have seen conflict but no warfare.
Belgium and the Netherlands.
Come to think of it, this is almost an exact parallel to Israel-Palestine in terms of mutual dislike of each other, Belgium being primarily Catholic and the Dutch being hardcore Protestant.
The 1830 separation was not bloodless, but both sides quickly got on and hasn't been to war against each other since.