Second Boyfriend 

Someone who is already in a relationship that you deeply care for and have a loving attachment to. The feelings are mutual between you two, so you make it unofficially official. You don’t want to share this person with anyone other than their significant other

“Monday’s are for second boyfriends”

Second Boyfriend by SecondgirlfriendNicki June 30, 2019

Second Boyfriend 

Someone who is already in a relationship, like yourself, that you deeply care for and have a loving attachment to. The feelings are mutual between you two, so you make it unofficially official. You don’t want to share this person with anyone other than their significant other. You’re in a relationship with each other on the side.

When you have more than one boyfriend

“Monday’s are for second boyfriends”

Second Boyfriend by SecondgirlfriendNicki June 30, 2019

Wifes Second Boyfriend 

Just another name for r/WallStreetBets

I lost money taking my investment advice from my Wifes Second Boyfriend.

Really, by time the Wifes Second Boyfriend yells about a stock, you're usually too late to do anything about it.

Wifes Second Boyfriend by Krashlia March 9, 2021