There’s a range of views on gender, relationships and marriage customs across Vendrith, but there are some commonalities that extend across it.
Marriage and life-long (or indefinite) pairing with a partner exists in most cultures. The views on how mandatory this is to engage in romantic and sexual activity and how exclusive marriages should be as such varies, as does standards of exactly when it should happen. Many envision life as a 3 step journey: first alone and growing, second as playfully exploring, and third as wisely committing to one (or more) partner(s) for life.
Marriages are usually performed by one’s holy community (if applicable), though in other cases it is sometimes done by the elders/leaders of a tribe, village or society. How socially acceptable it is to end a marriage varies, though usually betrayal is viewed as worse than a mutually agreed end.
While monogamy is likely the most commonly practiced form of romantic relationship in Vendrith, the world has a long and deep history of polyamory and polygamy. Some cultures revere the practice of three-person-polyamory as a part of the Trinities, with such marriages (especially for important, holy or heroic people) being considered quite the event. In others, it’s so important to form a trinity of sorts that in even a marriage of 2 people, the person that initiates the marriage is considered a sort of third - called a God-Partner. This person is meant to be a trusted friend or mentor of the couple that can be approached for help, such as to simply discuss or confess about matters of the relationship, or even to mediate and counsel between the partners when needed.
Most people partner up across gender lines, though homosexuality is common and accepted as part of life. Exact visions may vary a bit though, with gay relationships sometimes being viewed as having different standards and levels of gravitas. People aren’t necessarily considered by society to have orientations so much as preferences (whether the person feels it or not), and it’s not considered crossing any sort of line to dabble a bit in a sexuality one hasn’t before. Some cultures view homosexuality as a youthful thing, and not something as long term or serious as “proper” marriage. Interestingly, some of these cultures then consequently do not see flings along gay lines as a violation of marriage (but more like a distraction). It’s sometimes considered best to conform to a heterosexual marriage of convenience, whilst agreeing to allow continuing one’s preferred activities on the side.
Magic and alchemy allows for the changing of one’s sex, either slowly or rapidly depending on the solution (the latter being harder to come by). Gender as a social role matters to most culture’s customs and expectations, but the ability to change ones gender is widely accepted so long as one adopts the customs of the new gender one takes on. While it varies in relevance, the concept of a 3rd Gender has existed and continues to exist in many cultures in Vendrith. The changing of sex and/or gender appears in some cultural stories as an element signifying a hero’s self-discovery and renewal after a journey.