@Wowzah i think it's obvious he's pregnant by now. Every time he's tried to take the pill, his body rejected it and he'd thrown up. Euihyun thinks he's not pregnant though because the pill he got from the doctor, he doesn't remember when he woke up and threw up.
But I think in this chapter TaeJu is just mad at himself for making Euihyun think he had to go through going to the doctor alone. That he was more concerned with Euihyun berating him and getting upset with him, rather than just be concerned about Euihyun's health.
The neighhour had spoken to TaeJu (though we, the readers never got to see the convo) but it was probably about how sick Euihyun was before, which is the only way TaeJu would've known about that.
Also, the author has drawn several little artworks on their twitter with Euihyun and TaeJu with twins in the past.
But I think in this chapter TaeJu is just mad at himself for making Euihyun think he had to go through going to the doctor alone. That he was more concerned with Euihyun berating him and getting upset with him, rather than just be concerned about Euihyun's health.
The neighhour had spoken to TaeJu (though we, the readers never got to see the convo) but it was probably about how sick Euihyun was before, which is the only way TaeJu would've known about that.
Also, the author has drawn several little artworks on their twitter with Euihyun and TaeJu with twins in the past.
Whips and Chains excite me.