Will the gap that keep appearing between my front teeth KEEP coming back after my braces are off?

I have had braces on for about a year and a half now. I have a problem where my front teeth keep pulling apart and leaving a gap. My orthodontist puts a rubber band thing around them and pulls them back together but then when he takes it off, like clockwork, it opens again. When my braces are removed in a few months, will this problem continue? How can I stop the gap from coming back?