Don't forget that EK also follows that up with:
In a number of permutations. Ian is aware that there's no white picket fence future for his relationship with Minerva. It doesn't mean it's a "dead end" when he isn't looking for such resolution but just some enjoyable sex on a side to begin with.
In this context Minerva not being lifetime option isn't a red flag as they were discussed, but a bonus. They can fuck without fear that Minerva will suddenly try to baby-trap Ian, like some other certain LIs.
(also, i don't want to make unfunny joke even more unfunny by explaining, but i was mostly tapping into a connection between
old and
dead there. It wasn't meant to be a serious objection /s