I have to say, I am very surprised by how well the Author wrote this chapter, it's the first time I have seen a manga where the MC has had several girls to pick and choose from, where he has legitimately not thought of any of the girls in a romantic way like that except for maybe one single one of them all, and where the MC has handled a confession like Isis' so adult like.
The way he handled that, really shows how mature, respectable, and caring he is, and I hope he follows through with his words, that he takes time to actually think about romance and everything that comes with that, and figures out how he feels about whoever caught his interest the most, who he likes and wants to be together with, and whether he'd feel comfortable having two - in the future - wives, or if that would be too much for him, if it would make him feel that he'd be unfair towards the second wife as he doesn't think he'd be able to give her the same affection and time of day as the first wife would receive.
I think these kinds of thoughts and thinking is something that he's capable of doing, based on this chapter, and I hope that's at least somewhat the direction that the Author chooses to take.