I cheated on my wife during third trimester. It was random but i did it twice. Its eating me up! Keeping mum seems like my best option...any thoughts?

It's good that you regret a bit. It shows you still care for her, which suggests that you don't want to break up with her. And if you want so, you need to tell her upfront. Knowing it could result in a straight divorce, I'd still take the courage and say it. You both need to be honest to each other, come whatever may. Now, considering if you don't say - your life would just keep going normal, but it'd always keep eating you inside. I'd only suggest it if you can decide you'd never do it again. If you do, you'd yourself break up considering you're not worthy of her. Be true to yourself.