A Foible

I've run into a problem with my writing that I foresaw earlier, but hoped it wouldn't be too much of an issue. I'm writing Summer Story in the POV of two different characters (first person present tense, which is brand new to me...I think) and although I have a rough story arc for each character, I haven't planned enough scenes in one of the MC's view. Seriously, I have about 40 scenes sketched out...and about seven or eight of them are in his POV. I need many more scenes for him, and I believe I could plan some if I weren't so pressed for time. As it is, I'm having trouble moving past the parts where I need to put a scene about him in.
I mean, I don't want to just have a couple of scenes for him. I have a lot of info for him and I want to include his voice...plus, it adds tension if I end a chapter in the POV of the other MC in a cliffhanger and then go to the problematic MC's view and write another chapter with another cliffhanger but in a different scenario, and so on.
Right now, I have three separate pages in my WIP that say, "CHAPTER #--CHARACTER NAME" and nothing else.
So...it's bothersome. I'm afraid I'll reach the end of my scenes and not have 50K. And then I won't know what to do until I'm able to plan more.  I am not good a planning under pressure.
Have you ever had a problem like this? Any advice on how to deal with it?