Your email indiscretion was a long time ago and it appears you have a decade long track record of managing your own business. I think there are potential employers willing to overlook something that happened 10 years ago. Talk with contacts you have developed in your ASIS local chapter or the larger ASIS organization to let them know you are looking for a corporate role. You will hear whose hiring and you can ask your security industry peers to serve as references should discussions with a possible employer advance.
Security issues and trends have changed a lot over the last decade so it’s good that you have maintained your CPP designation in order to stay on top of things. You clearly have an entrepreneurial bent so you may want to consider security consulting while still operating your current business. As you handle security consulting assignments for your clients you could become a known and valued resource and that may result in you being asked to move “in house.” That’s the longer path to a full time security role, but it happens regularly with consultants.