find with regex

[bdoremus]

I'm battling find right now.

I want to find any file that matches a path governed by the following regular expression: "(monthly|nightly).[0-9]+/home/(user1|user2)/.mailbox/"
to match files like:
monthly.1/home/user1/.mailbox/mail.txt
nightly.15/home/user2/.mailbox/cur/mail.txt

I've tried:
regex1="(monthly|nightly).[0-9]+/home/(user1|user2)/.mailbox/"
find ./ -regextype posix-egrep -regex $regex1
and it just spins and never gives me an answer, even though the file structure isn't that big.

what am I missing?

[bdoremus]

anyone have any ideas?