The chances that she will be pregnant when she returns to you are very very high.
Turn up the volume. That's insaneš³
You smirk seeing your wife's body so aroused by the sexual lifestyle you both now embrace. She has a boyfriend now and though she doesn't fuck you anymore, the intimacy in your marriage is greater than ever before. She shares her body with you after him and you crave that. Now seeing her body around your home, you realize you're more aroused by her than you have ever been, and another man is enjoying it. She smirks at that arousal. She'll even be excited by it. And she's never shy taking a seat on your mouth when she's excited.
When you're a cuckolded husband, it may become awkward at times when she has enjoyed that freedom. You both go to the same gym, and you know she's bedded a couple of men there and even encourage it. But when you're in the locker room and one man is bragging about her to another you felt that initial angst when he talks of her being married. But when he describes the sex and says how amazing it was and it was the best he's ever had, angst turns to pride. A cuckold's pride.