I might get chastised for this, but I did the opposite of waiting.

We were both in med school, taking our final lincense exam before trying to obtain residencies. Yes, I understand that everything was on the line for both of us. 

After I finished my last rotation, I packed up and moved home (10 hour drive away). She was doing a rotation in a diff part of the country so I knew this was going to have to happen on skype or the phone. 

When I got home, I tried to reason that waiting the 3 weeks before her exam was the reasonable and considerate thing to do. But I couldn't do it. I called and ended things. 

Here is the context - in our 3 year relationship she had cheated numerous times. I had chosen to forgive her each time (yes I know... I'm stupid, but I deeply loved her) but every few months something new would happen. Additionally I was constantly the supportive one and recieved no support.

Here I was, in a different country, stressfully studying my ass off, with no family or friends for support (I moved around for rotations every few months). 

When I finally got home, I knew I was done supporting or caring about someone that I finally realized didn't care about me the same way. I wouldn't say she was a bad person, but someone that was so wrapped up in themselves, everyone else came a distant second. Took me a while to see that. 

I started thinking about myself for the first time in my life. The guilt disappears and I did whatever I needed to get my life back. 

So, maybe your situation isn't as extreme as mine. But it's not selfish to ask yourself what impact staying with someone for a few more weeks will have on your own emotional and mental self.