First of all she would have to be in agreement, second that she wanted to watch and masterbate as I suck her husband, and third she would be willing to fuck me in any way I wanted, especially take me in all of her holes. Under those conditions I would suck him and swallow his load.
I ask my partner where she wants me to cum. Only pull ouy if she says something other than inside her. Sometimes my wife tells me she is thirsty while I am fucking her meaning she wants me to cum in her mouth.
I have enough scares on my body from accidents and military service, I'm sure not going out and pay for more permanent scares.