
I don't think chief is married to a woman and mama is just the wife they all keep talking about. In this page, the seme asks "Mama... did your husband cheat on you again." I think he's talking about the chief and if you look at this page, http://www.mangago.zone/read-manga/yoru_ga_aketemo/bt/306520/Ch5/25/ The uke is like "Wife? Chief, you're not single" and then Mama/wife runs in to yell at chief. Also in the bottom right hand corner the seme is talking about how you don't need to see rings on a couple to know there married. "At bar" part don't make sense so I just assume they mean gay world because there still some place in this world where gay people can't get married. I'm going to take it the chief does not wear a ring because the uke seem surprised the chief was taken and if he had a woman as a wife I think she would be pissed if he didnt wear a ring. I also think if the chief was married I don't think the wife would know where he would be because what cheating husband would tell his wife where he goes to pick up men or woman. He could tell his wife which bar but I think it would be weird that he seems to be hanging out in a gay bar. The page also happens to say that Mama maintains contact with other bars to exchange info.
Sorry I talked to much but once I started to think about it I couldn't stop. I had the same question after I read it. Well that is what I think anyways. I just really want to see a story now about chief and Mama. I want to see Mama give that chief a licking and be like ha it serves you right. Then as Mama is messing with chief and seeing chief being all pitiful we get to see a bit more of the uke and seme.

Lady earthly gave it in their explanation upwards:
http://www.mangago.zone/read-manga/yoru_ga_aketemo/bt/306520/Ch5/25/
i love them, they are working hard on their romance.
Also is chief married to Mama or to a woman?