If you like romance stories with older men, I would highly recommend Lip Smoke. This is the manga that got me into older guy romances, and so far I have not read anything else that tops this. I really enjoyed the story and I wish it was much longer.
Setsuna gets a job as an assistant to Kazuki, who writes erotic novels. They spend time together and go on pretend dates in order to help Kazuki gather inspiration for his next book. They share several cute physical moments between them. I like how Setsuna is not the typical wimpy, crybaby female protagonist. She is strong, mature, smart, and not afraid to speak up and express her feelings. The art is good and the way she is drawn makes her look attractive.