Here, have some musings (and let me know if you even enjoy reading the semi-philosophical stuff I sometimes spew at you). XD Disclaimer applies.
Bonds
Everyone is this world is bound to another person in some way, shape, or form. Some are bound to many people, and others are bound only to one. Bonds exist between all sorts of people: lovers, friends, enemies, and family. They know no gender, race, or creed. They simply exist, uniting the human race in both helpful and harmful ways. Some cause the soft, heaven-inspired light of love and peace, while others stir up the scorching fires of hatred, rivalries, and war. Some bonds are light and waver falteringly, threatening to fall apart at any moment. Others are strong, drawing two people closer and closer together even when they try to break apart. All bonds are invisible, meant to be felt rather than seen.
Some bonds are powerful enough to be felt by outsiders who are simply in the presence of two strongly-bound souls. Such a bond must durable enough to surpass the test of time and the trials of life. The chain that binds two such people must be made of the toughest material, but it also must be light enough to not drag its captives down. It must be long enough to allow the two people to be independent, but it must also be short enough to keep them from straying too far apart. The chain must be loose enough to allow its netted souls to breathe, but it must also be tight enough to prevent its own removal. Anyone who experiences such a rare bond even once in his or her lifetime is very fortunate indeed, but the fortune of one who lives the life of a soul bound to such a chain is perhaps tenfold that amount.
Everyone who has been in a room with Roy Mustang and Riza Hawkeye has certainly felt such a perfectly tempered bond, whether or not they were aware of it at the time. Every time the soldiers were separated from one another, the chain between their souls tugged them back together. And every time they were brought back together, their mutual links grew even stronger. After many years, their connection would prove to be unbreakable, withstanding even the strongest of firestorms which would melt any other chain. Truly their ties were so sturdy, so permanent, that if one of them passed on to a different world, the other would soon be pulled into the afterlife with them.
Such bonds have a terrible beauty to behold, for as much strength and endurance as these chains provide, they also allow two people to be defined by each other. Without one, the other is sure to be lost. Fortunately for Riza Hawkeye and Roy Mustang, they never have to discover what it would be like to lose the other permanently. They may have come close many times in the past, but chains such as theirs have a way of keeping the bound alive for no other reason than their partner's continued existence.
There is no way to rid oneself of these perfectly bonding ties of fate: they remain forever a blessing and curse upon those who are held by them. Roy and Riza have always been and shall always be drawn to and defined by each other. And, truthfully, they wouldn't have it any other way. It is what makes their intertwined lives unique, memorable, and, most of all, stunningly beautiful.