Ask relating to a Patreon side story (includes spoilers)
I haven't really considered an alternate timeline. I did answer another "what if" style ask about this a little bit ago, but I haven't put much thought into it outside of that. I guess, no matter how angry Konstantin was, I don't see him actually having Tereza executed or banished (even if he says he would have). Tereza being pregnant was just the excuse he gave himself to do what he already wanted to do. So I think even if she wasn't pregnant he would have found a different one.
For a man that likes to portray himself as very pragmatic and logical, almost all of his decisions are based on instinct or emotion, especially the ones about his family. And I think no matter how much he might want to, I don't think he'd ever bring himself to actually hurt Tereza (or any of his other wives). And what he told Tzesar about never moving on from people you love applies to Tereza in equal measure as it does to Gulin.
If such a world where he did execute Tereza ever managed to exist, I think he would actually be the most miserable of anyone, and would probably become very reclusive afterwards. And he probably would grow to resent Gulin afterwards for letting him kill his own wife, so even he wouldn't be happy in this AU.