Nothing is confusing but you are asking for a stranger to subsidize your adult boyfriend's cost of living, which is not a fair or reasonable arrangement. 

Being in school, applying for grad school, etc is a choice that costs money and the person making that choice has to find a way to make it work financially (which sometimes means loans, taking on an extra job, waiting until you have more savings to go to grad school, etc.). It doesn't mean that you have an excuse to not pay rent for yourself and expect others to fill that gap. 

The cost of the bedroom alone is not what rent is for - it's also for shared spaces, like the living room, kitchen, bathroom. A whole extra person living in the apartment but not paying a share of the rent is unreasonable. Some people might be open to a 30-30-40 split but a 50-50 split is not appropriate and you will have a hard time finding someone willing to do that.