The Mandalorian marriage vows presented in the Republic Commando books, spoken by Torian Cadera in the Star Wars: The Old Republic video game, and the most well-known Mandalorian vows are: Mhi solus tome, mhi solus dar'tome, mhi me'dinui an, mhi ba'juri verde. We are one together, we are one apart, we share all, we raise warriors.
Alternative (and lesser known) Mandalorian marriage vows that Akaavi Spar offers are: Ni vore gar riduurok. Gar riduur. I accept your love bond/marriage arrangement. You are (my) spouse.
The few instances we see of the exchange of these vows in the source material are simple: One person says the vow, the other person repeats it. The vows can be exchanged in person or through voice or text messages.
Per Karen Traviss, who expanded the Mandlorian culture, https://archive.org/details/sw-insider-86-online-supp-mando-a-culture-and-language:
With the Mandalorian preference for less talk, more action, dating is considerably streamlined and to-the-point. "If you want to do more than just get to know the Mando guy or gal you fancy, or gaze at each other over a pint of net’ra gal, then you better be serious about it or else you might get the prospective parents-in-law showing up with blasters," Traviss warns. "These folks are regarded as adult at 13, and they tend to settle down early. Mandos don't like to lose people from the community, either, so 'marrying out' is a blow to them: they want people to enter the culture rather than leave it. The cultural pressure is to get hitched, because strong family units are the core of the community. They're a lot more relaxed within a Mandalorian community, but if you're from outside, attempts at casual romance of the physical kind will be seen as a threat until you show signs of joining them."
You might as well forget any idea of a lavish wedding, too. As seen with their rather blunt vows in the Insider article, long celebrations to declare undying adoration isn't their way "Mandos know what they want and they don't beat about the bush: they get on with it," Traviss says. "Why have a long ceremony? Commitment to each other, whether together or separated, and to the kids you bear or adopt, is everything. Husband and wife have equal responsibilities. They don't need to say any more than that. They'd be appalled by our western tradition of spending more time planning the wedding gown, the guest list and the flowers than working out what to do with the rest of your lives together I can almost hear them: 'All this effort and waste for one day?'"
Legacy of the Force: Revelations has a wedding in it, which (unlike the marriages described in the Republic Commando books) had a party afterward. In a couple of "weddings" in the source material, one spouse gives the other one an expensive gift (typically, a gem that can be turned into jewelry) as a sign of commitment.
Per Legacy of the Force: Revelations: “A Mandalorian wedding consisted of four short vows and was usualy a private ceremony for the couple, not their families. Fett, still thinking in aruetii terms, wondered whether to feel offended that he hadn’t been invited, and then realized nobody else would attend, either, although there’d be communal drinking and sentimentality afterward. Not a credit would be wasted on fripperies. Mando’ade operated on plain, honest pledges and contracts, in love as well as business. ... The celebratory feast was packed; guests had spilled out from the courtyard onto the grass outside the low retaining wall. ... She could stil hear the wedding guests singing—that same plantive ballad she’d heard the other night. ”
Per Legacy of the Force: Revelations: “Mirta turned her back on him, displaying a saffron plate decorated with gold sigils and glyphs that he’d seen on the Vevut clan’s armor. She was definitely serious about Ghes Orade, then. That meant Fett would have a grandson-in-law soon, and with it a kinship to Novoc Vevut and the rest of the clan ..."
Per Imperial Commando: 501st: “A betrothal token should be portable, capable of easy conversion into credits in case of emergency, and, if worn, should not impede the wearer in combat. Earrings are out. So are long chains. Gems in rings should be in a rub-over setting and shallow enough to be worn under gauntlets. You really don’t want to see what happens if you catch a ring in a moving cable or machine part. — Purchasing advice for Mandalorian suitors from Tsabin Dril, jeweler and artillery specialist."
In the Star Wars: The Old Republic video game, Akaavi Spar gives her spouse her father's helmet as a betrothal gift, while Torian doesn't give anything tangible.
In fan fiction, armor pieces or the chest diamond are exchanged. (If this based on something in the source material, I don't have a quote. Note that armor pieces are custom fit to the person, so exchanging armor would be impractical for most partners in actuality.)
When one person marries another person, a decision must be made about which clan to join and if there is any change in either person's surname. The source material offers a variety of options. Most married partners join the clan with the most resources and take that clan's name as their surname. Some partners keep their given names, regardless of the clan joined. Fans theorizes that partners could start their own clan, could join the lesser clan if there are problems with the more powerful clan, or could join a dying clan to boost that clan's numbers.
Although there is a word for divorce (shuk'la riduurok), the author did not provide the exact phrase that needs to be said to perform a divorce. Triple Zero provides a little information about the process: "... soon Ilippi [spouse of Kal Skirata] and the boys and his daughter were no longer waiting when he returned from the latest war. Ilippi divorced him the Mando way, same as they’d married, on a brief, solemn, private vow. A contract was a contract, written or not." The implication of this section seems to be that it can be done by any spouse in the marriage, at any time, without conferring with the other, and that the other (or others) in the marriage was obligated to honor it. However, this is only one person, so we don't know how complicated divorce can get for Mandalorians.
The author also did not create a canon word for a former spouse (unlike with a former parent). Basing it on the construction of dar'buir (former parent) and on knowledge of the construction of other Mando'a words, we could assume that the word for "former spouse" is dariduur. However, because this is a fan construction rather than something that the original designer of the language and culture created, we can also assume that being a "former spouse" does not have the same stigma as being a dar'buir does.