I recently moved hosting of my domains over from a managed hosting provider of several years to AWS. While there is the inherant time sink of managing the infrastructure yourself, I didn’t want to maintain an e-mail server.
My domain registrar, gandi, provides 2 free e-mail addresses per domain, and unlimited forwarding accounts.
While your domain may be hosted on AWS (using aws nameservers), you can update the dns configuration to point to gandi’s mail servers, and setup and manage all your domain name e-mail addresses from gandi's console.
This is managed in you aws console under Route53, Hosted Zones, . You'll then want to create two record sets for the domain as follows:
|TXT||No||10800||“v=spf1 include:_mailcust.gandi.net ?all”||Simple|