I agree waiting is the right thing to do, but as someone who has been in a similar situation (as the one who was to be dumped), I will say this and please don't forget it, OP: be mindful of how you will treat her. You already know this is to be over, so you could be checking out of the relationship without noticing, putting less effort, treating her coldly, etc. My ex didn't break up with me when I was facing a super stressful deadline, but he ended up treating me so badly that during the last few weeks I felt like he already left our relationship and just didn't mind telling me. It hurt me, made me resent him and I ended up breaking up myself before he got himself to do it. It was a very shitty situation.

Don't forget that you're deciding to stay, why you're doing that and how much you care for this person.