In case anyone is wondering WHY a nomad woman would marry one of their conquerors, here's a list of motivations I can think of. Marrying into whatever tribe you're in was normal, and generally didn't involve rape.
Bronze age drives for marriage
Sex drive/maternity drive
Both of these are primarily biological, and really focus more on having sex than marriage directly... but through social and economic pressures tend to be mutated into that. Ymaryn warriors are PROBABLY sexier (on average) than any other social class of any nearby polity.
Hypergamy
Women statistically marry across and up dominance hierarchies. It's probably their most robust tool for social mobility, since it has been somewhat available even in the most oppressive societies. In the Ymaryn, this means women are far more likely to marry a warrior than a half-exile. They and their children are then less likely to become half exiles in the future, and far more likely to have advancement opportunities.
Social ostracization
Most societies treat non-married people of marriageable age as weird. Given the high mortality rates, NOT contributing to reproduction is ODD. And make no mistake, human societies are like dog packs: if someone is unstable and behaviorally weird, kill them. Or at least ostracize them as a quarantine of the weirdness. It's part of the social immune system, keeping society functional by mandating a common standard of behavior. It's also why large societies tended to abuse homosexuals.
The Ymaryn are way ahead here though, with the same solution as medieval Europe. We provide one positive path of both advancement and mild quarantine: the shamans (monks/nuns for medieval Europe). Still, in spite of that release valve, there's a pressure to be normal and get married.