Advice please

Okay so I'm in a rough spot. A few years back I had slept with this guy (I'll call him tom) who I had known from school and mutual friends. It was a one time thing and we both had a mutual understanding of what was going on.

So now back to the present, I work at a coffee shop and my coworker (I'll call him Eric) and I have gotten very close. We have a lot in common and our personalities mesh so well together it's wild, I'm crazy about him. Well it turns out they are brothers. Who knew...

I see a future with Eric. We haven't even slept together because I feel like he should know what happened.

What should I do? Should I tell him? How would I even go about it!? Also Tom still tries to send me pictures and message me to meet up again but I always ignore it. Eric and I are talking but keeping it between us right now because it's still fairly new.