Re: Staying motivated
One thing I do in regards to training and teaching is that I look to train just like everyone else. I demonstrate the technique, then get a partner and start training just as any other person in class would. In short, teaching does not have to mean "not training" if you do not let it or want it to. I think that is the first place to start - a change of perspective.
After that, you can look to things that make this more doable where you are. Some of the things we do in our dojo are: we train in only one to three techniques per class; we carry a single theme/principle for a week or more; we rotate two to four times per class on the same technique; we have advanced training hours; we offer training several times a day, daily. All of these things work to limit the downside of not being 100% instructor 100% of the time (i.e. looking over everyone's shoulder all of the time) - which isn't necessarily all good either (my opinion).
Another change of perspective that you can apply, if you are not already doing so, is to look to work on techniques you have questions about and/or problems with - vs. picking techniques you feel comfortable with and/or that are fun to do, etc.
Additionally, if the learning curve is very low, due to too many beginners on the mat, you can always look to delve deeper into any given basic - finding the ocean of information within the "simplest" of fundamentals. These last two suggestions might help with the sense that teaching means not learning - which is not true for more reasons than just "you learn a lot when you have to teach something."