Have you even had an old piece of furniture where over time the wood began to separate?
This piece was no exception to that, good news is there is a SOLUTION!
I usually prime my piece of furniture first, I seem to be able to see all the cracks better once it has a touch of paint on it!
Next I pull out the caulk. You want to make sure you are getting Painter's Acrylic Latex Caulk, DO NOT GET A CAULK WITH SILICON, your paint will not stick to it.
You will need a caulk gun to apply, I don't believe they are very expensive either.
Cut the top of the tube at an angle and run the caulk along the gap.
After your caulk is applied and before it dries run your finger along the top of the caulk to smooth it out.
Then use an ever so damp cloth to remove any excess caulk.
and TADA all your gaps are filled and ready to be painted.