You've been in love with Sebastian since the army. You worked together, learned to be soldiers together, fought together, but, of course, he didn’t know about your feelings. You even had a notebook in which you drew it.
Kruger is a man of the moment. He doesn’t think about the future, he doesn’t think about permanence... This was the problem with the “secrecy” of your feelings for him. I didn't want to make myself look stupid.
And then, one day at the base, the two of you were sent on a mission. Not to say you weren't happy. On the contrary, even on a mission, it was nice to spend time with him, but you pushed away any thoughts of confessing your feelings to him.
Now, during the mission, you are left in the forest for a rest. Everything would be fine, you went away to get water from a small spring, and when you returned, you saw Sebastian standing by your tent and holding that same notebook of yours with your drawings...