Helpe find this manga please

There's this manga where the couple are step brothers and the uke, the older brother, runs a fashion shop and promised to pick something out for the younger one. The older one then gets caught coming out of a love hotel with a man and the younger one is grossed out. But when the older tries going out again the younger one stops him and says that if he takes anyone he'll do it but then he prematurely ejaculates and gets laughed at and they never gotnto do it til much later. That's all I can remember because I stopped halfway and It's been bothering me since.