Preferable datacenter set-up for external services

I have a use case, where I need to set-up consul servers (infra) in two different physical datacenter (which is a private data center in our organisation) to make a resilient infrastructure. Here our services are desktop services which are running on client’s machine ( a windows machine). In our case, thousands of client machine we have with 10-15 services running there. And we are using catalog registration for registering those service with consul.
Now question is, since we having 3 servers and 2 physical datacenter (private), but we have set up only 1 consul datacenter (dc1), so do I need to set up 2 consul data center to make it resilient?
But then how data will be replicated among those two datacenter, if one gets failure or down?