The return address on wedding invitations isn’t something you necessarily wait until mailing time to deal with. Instead it can be planned for much earlier.
When ordering your invitations, there is usually an option for having a return address printed directly on the back flap of your mailing envelopes. There is a small fee for this additional printing but it eliminates having to either handwrite it or prepare and stick labels on later.
When professionally printed on the envelopes, the return address normally includes just the two lines of the address…no personal name.
The important thing is to remember to include a return address on your wedding invitations, no matter how that is accomplished, so the Post Office can return any undeliverable envelopes.