I too am a mom who bakes for her boys, and although I am far from an "expert" baker, I often had crumbly loaves when I first started baking. There may be many other reasons for this, but the one I am sure was responsible for slices that fell apart, was letting the second rising go too long. Being so busy, I'd often forget my rising loaves, then would find them "too big" but would bake them anyway. Time that second rising carefully, and, if they are left too long, it's best to punch them down, reshape them, and let them rise again. I've also found that breads calling for mashed potatos come out nice and moist, as do ones that contain oatmeal. I do hope this helps--just don't give up! It's a wonderful thing to do for your family.