Can I use my Sprint iPhone 5 on Verizon's network?

I bought my phone thru sprint on my mom's plan. I'm needing to separate my account from hers. However, my fiancé gets a discount through Verizon because of his job so I was considering getting us a family plan thru them but want to keep my phone. Is this possible? It's brand new and I'd hate to lose it because of a new provider.

No the phone is yours, you can do whatever with it

No, sprint phones only work on sprint.
It will not work on Verizon or any other carrier

Unfortunately, once you have a certain provider for an IPHONE, it is linked to that provider. Apple is tricky about this kind of stuff. You can however, jailbreak your iPhone and buying a non-approved Apple app that will bypass this and connect you to any network in the US. Obviously you will need some help jailbreaking, so let me just run through that real quick.
1. Locate your Apple Version. (Settings, General, About, Version 5. X 6. X etc… )
2. Type in "Google" iPhone Jailbreak for version ^^^^^
3. Click on any link and find a jailbreak for your version.
4. Download and install to your iPhone (there will probably be detailed instructions when you download).
5. Congratulations!
Side Note: If you decide to jailbreak, you will want to first create a back-up of your data from your iPhone through iTunes because you will not be able to update your iPhone after you jailbreak without restoring your iPhone to factory settings.
Side Note II: If you can't find a jailbreak for some odd reason, I have a couple of options for you that you can type into "Google" for a jailbreak.
a.jjailbreakme
b.eva3ion (my trusted source)
c.redsn0w