@Sweetiepie352,
That's a lot of drama for everyone.
Start by moving out.
You need your own place - get used to being independent.
Let your ex and her new ex sort their own thing out.
If you and your ex want to try being friends and start fresh, give it a chance. Be friends, not romantic partners.
Get on with your life while your former partner deals with her relationship with her new ex.
You're way too young to be caught up in the middle of all that. Don't encourage the drama and don't be part of it. It doesn't do anyone any good.