It depends on how MUCH they are moving. All teeth actually move ever so slightly. Sometimes it is enough for only you to notice and nothing for concern. But no, your front teeth (or any teeth) should not wiggle about or be loose.
Part of it, as Boldyloxx pointed out, would be related to any other dental work you may have such as fillings, bridges, crowns, etc.
Part of it may also be tooth/gum exercise (or lack thereof). That means flossing, as well as certain types of brushing and possibly using a special rubber thing to exercise the teeth and gums.
Another part has to do with nutrition. What do you eat, how is your overall health.
There are also herbs that can strengthen teeth and tighten gums but I am no expert in that department.