Take care of yourself.

It's natural that you will spend less time with your brother as you develop a romantic relationship. It's different for you and your family, but it's really important for you to develop relationships outside of your family as well.

The job is important, though. It sounds like you have a really good head on your shoulder - you know that what you have been doing (showing up late for work) isn't good for you. I think most of us tend to sort of 'forget' the basics when we first fall for someone, but reality creeps back in soon enough.

In my experience, it is just a bad idea to ask or tell detailed information about sexual history -- as you are learning now It's find to have conversations on a sort of philosophical level, but detailed information isn't going to make anyone feel good. She is with you now, not those other people, so just remember that and let history be history.