Failover IP to remote host in IPSEC tunnel - Pfsense

I have a site-to-site IPSEC VPN with a partner. They have two routers, each with its own public IP. We are connected to one of those, but sometimes it goes down and I need to go to Pfsense and change the host IP in the VPN configuration so I can connect to the alternative router.

Is there a tool I can use to make the switch automatically?
Ideally, when the connection to the main IP fails, Pfsense (or something else) switches to the alternative automatically.