Weird dream of my significant other getting laid

I have been having this crazy dreams lately where i go home early from work and is a car in our driveway and i park in the street and i sneaked in the house by the back door where the alarm door dont chime to find my partner getting laid by another guy(sometimes with a guy we work in same office and sometimes with a stranger. I sit back and let them do the deed, like i want to say something but i can't. i get petrified watching. whta would this mean?