Returning Values from INSERT ON CONFLICT DO NOTHING

Hello,

I want to use the "UPSERT" syntax for returning an ID if it exists, or
inserting a record and returning the new ID if it does not exist.

INSERT INTO users(email, name)
VALUES('user(at)domain(dot)tld', 'User')
ON CONFLICT (email) DO NOTHING
RETURNING user_id, (xmax::text::int > 0) as existed;

When an email address does not exist then it works fine and I get the new
user_id, but when it does exist, I get no results at all.

How can I get the results in case of a CONFLICT?

Thanks,

Igal