THREESOME?

I've known my coworker some months I've hung out at her house a couple times.. While I was there her husband was nice nothing out the ordinary but she sometimes make little comments at work so she finally asked me to join them in BED like a THREESOME. Now I'm not gonna lie its kind of on my bucket list lol and there both attractive but for some reason I can't stop thinking bout the after effects I told her sure I'll come this weekend but having doubts. Should I do it?