Responses
This manga's cover changed I think so now it's sexual but the plot is similar to what you described
Papa Datte, Shitai
https://www.mangago.zone/read-manga/papa_datte_shitai/
This one's cover is similar to what you described but not the plot :
Daraku Kazoku-ron
https://www.mangago.zone/read-manga/daraku_kazoku_ron/
I don't know the name i remember the cover though it was like something with two men and a baby I think the other guy was taking care of the baby and the other one joined in? It had friendly cover not a sexual looking one ┐(´ー｀)┌