I've read every novel (up until a year or two ago when I forgot to buy more) and I'm not sure that there's anything to this.

The Battletech books from before the Clan invasion had female characters written almost exclusively to be love interests. I'm re-reading them all and boy, are those parts cringe. There's only a dozen or so books pre-Clan, but if you read them you'll see what I mean. Most of the time, those characters can't pass the Bechdel test in scenes by themselves; they're constantly thinking about a male love interest no matter what's happening.

The Clans have a totally different culture where people are bred in vats rather than being born naturally, and are all about glory and combat. Sex exists for fun, but not romantic relationships (mostly). As a side effect, the authors of those books had to write female characters that didn't revolve around a man.