likely the reason both have become spammed is due to your email behavior. If you get emails from people that have long forwards on them with lots of email address on them and you continue the forwarding then your email address is going out to literally thousands of people and those kinds of emails are quite often started by the spammers so that they can collect all of those forwarded email addresses. Makes their job so easy.
NEVER forward with addresses on the email, instead delete all email addresses and use the BCC feature anytime you are emailing to more than one person so that no addresses show.

It is a very good idea to keep more than one email address, always use one of the freebie web emails for anything you do online, like sign up for forums, or freebies, etc then that one email addy will be the one that will be sacrificial and can expect to get all the spam, that is fine just delete the spam and go on.
Keep your good email addy like the one from your isp for only business and important emailing. But if you do the forwarding thing and the people you email with also use the forwarding with out using the BCC feature then it really won't matter what you do your email addy will be spread and you will get spam.

Spam should always be sent to the spam/ junk file and then emptied from there so that your spam filters can learn, never just delete it. Some email programs do allow you to block addresses but that does not help much because they have tons of variations on them, they have it down to art form.
NEVER ever open a spam email they have code in them that sends back to the sender to let them know that is a good active address.

Setting up specific spam filters in your email client can help.

Thanks for the advice. I have two people that send me emails with long forwards on them, but I never send them on.

well since your email address is included in that long forward your email addy is getting spread and harvested from them.

What is the BCC feature?

"the BCC recipients are those who are receiving carbon copies of the email, but whose addresses no other recipients can see."
Blind carbon copy, it allows you to put multiple email addresses in the header but no one can view any of the email addresses so it keeps all the addresses secure and away from prying eyes, it is the least you can to to respect the privacy of those who have shared their personal info with you.
Every email client has the BCC option available, if you do not see it on your email client ask or try googling it.

"In email mailing lists the BCC field is traditionally used as a courtesy to people who are a part of the list. Even if everyone on the list was okay with everyone else on the list having access to their email address, having such a long list of emails poses a spam risk to everyone on it. Many spam lists are generated by the presence of viruses on a personÂs local computer, which harvests email addresses from received emails. A mailing list email can provide a huge list of addresses for such viruses, and the use of BCC means that such a list never exists on anyone except the senderÂs computer, greatly reducing the risk of a virus getting the addresses. "

5 Rules for Forwarding Email

a story about what can happen
E-Mail Forwarding Etiquette