Vaginal Stretching-Fact or Fiction?!

I've read numerous articles on this and had some personal experience as well. I want to hear your thoughts on having a partner with a large penis, and how your body adjusted. I have had partners with large penises and sex at first hurt a lot, but after a while it didn't hurt. This leads me to believe that my vagina stretched to accommodate them. I'm more curious about how long it takes for a vagina to get back to its size before the large partner...but also curious about other women's knowledge and experience on this topic.