The most unlikely parring of peoples, due to obvious issues of history, would be a human-elf relationship. Depending on the history of conflict in a region, this parring may be outright illegal by both peoples. Like other possible romantic parings with elves, while it may not be illegal, it is seen as not wise, irresponsible, not fair as the elf will far outlive their partner of another species and the elf, while still fairly young, will end up having to take care of their other-species partner who is elderly. Eleven parents try to impress this upon their children, but of course not all children listen and some end up heartbroken when their love ages out of life after a mere several decades to possible three centuries.
Some dwarves marry humans, depending on the militaristic history of the human society in the area. Some marriages are for dwarven money and resources and human noble titles. Fairly uncommon though again due to the aging-out problem.
The most common, and still not at all common, inter-species parring is that of orc and human, as both tend to have about the same life spans. After this would be ameya and dwarf, although under the societal expectation/condition that the ameya can no longer reproduce. This of course meaning that the vast majority of all ameya-dwarf unions are of ameya women past their childbearing years and dwarven males.
There are homosexual relationships as well in these inter-species parings, but they too are subject to the same aging-out problem.
In regards to the ameya, as there are so few in the Mortal Plane, it is a social expectation that every ameya able to reproduce will get married and have children (usually at least two), regardless of sexuality or want of marriage or children, and these marriages tend to be arranged once the ameya reaches the age of adulthood (somewhere between 30 -40 years old). Any dalliances prior to that are expected to be put to an end. This is true to varying degrees for both the dwarves and elves as well. Depending on the relationship a group of elves or dwarves has with their human neighbors it may be seen as an elf or dwarf’s duty to put more of their kind into the world to help keep humanity at bay – “Humans breed like rabbits and consume like locusts. If we do not keep up our numbers they will overrun us.” This had led some groups of elven, and to a lesser degree dwarven communities, to experiment with fertility magic to bring their numbers up. This has had mixed results and some fair number of mothers have died during pregnancy or childbirth attempting to bring more than one or two babies into the world at one time. Instead, some to many elven groups may expect their members of child-producing capacity to have several children over the course of their long lifespans, such as one or two every century. Some to many dwarven groups encourage their members to have large families, naturally, as well.
In regards to homosexual relationships amongst ameya, dwarves, and elves, this is not usually seen as immoral as much as it may be seen as unproductive in light of a particular community’s need to sustain its numbers (this is also true of some human communities). Some members of such communities may argue that homosexual relationships for adults of child-producing capacity is a misappropriation of limited time and energy that needs to go into the producing and rearing of young for the survival and benefit of that community. An individual only has so much time and energy and the offspring needs two, engaged parents, working together for the benefit of their young. Not all individuals agree with this. Some think that as long as both parents spend adequate time and resources on their offspring, the same as a heterosexual couple would, then if the parents are engaged in homosexual relationships with partners that they did not produce the offspring with then it is of no matter, and the children may end up with two extra parents. Different individuals have different views on this matter. The bottom line for many elven and dwarven communities trying to keep humanity at bay is that more of their kind need to be in the world.
Some amount of magical cloning has been used in desperate times, although this is unsettling to most, and raises the specter of inbreeding and it’s potential negative impacts on a community. Some clones may end up feeling as though they have been created to be nothing more than like livestock and/or weapons of war – more thing than individual.