And, for Igarashi, the seeds of doubt have definitely been planted...
As I've been saying for years (literally), Igarashi and Chiyo's relationship will not last the test of time until Chiyo becomes open and honest with Igarashi, particularly about her relationship with Ookuma.
Aside from being stressed from not actually knowing what type of relationship Chiyo and Ookuma had in the past, Igarashi might even wonder if they are even continuing their relationship behind his back. He will probably continue to wonder if he is being constantly compared to Ookuma so, like in this chapter, he will try to imitate him. He might even develop a severe inferiority complex. All of which will negatively affect their relationship.