Personally I use a paid business hushmail account that can be encrypted. You make up a PW (I have no knowledge of it) and that way no one, including a SO, can access or view our correspondence without it. The only downside is that it requires remembering yet another PW.
For the record, I have bought furniture from Kimmberly Capone Interior Design so there are non industry business's using female names like ours. This means an email address incorporating part or all of a brand name can be explained away.
I would also like to add that simply putting deposit or payment in full, whichever is the case, on an e-transfer is best. Some try to get creative, stating something related to their business, which covers their butt but not mine. Neither the bank nor RC know me as Sophia, so even putting my stage name could be problematic for me. The other option for a deposit is a GC. Most ladies indicate what they'll accept on their sites.
I hope this helps!