Definetly
I really don't think he just did it for that, since in this new chapter he kinda addressed that people see his relationship with Masato as convenience because he can't have children. Honestly with all his backstory, no wonder he's as emotional constipated as he is. Not only his dad abused his family, but he also was reduced to a broken man because he's infertile, and that shit sticks with you hard.
I honestly understand why he has a hard time with feelings but I also understand why people can get desperate at it, specially because he's with someone as emotionally open as Masato. I'm sure he will eventually tells him that he loves him but he obviously needs time, after all they have only been together for six months. Your last point is right tho, even if he makes it as a joke so Masato gets jealous, it's still not a good look.
I been waiting for Asahi to tell Masato I love you, but is kind of sad how Masato is committed into the relationship and willing to make things work and Asahi doesn’t look the same way. Honestly this was coming and I wouldn’t be surprised if they break up. Since they starting living together, for Asahi’s side it seems like it was just for company, food and maybe sex, plus I don’t like how he constantly talk about big breast women on Masato’s face, that for me is a red flag.