Hi, ive been with my gf for 6 years now and about 6 months ago we were going through a bit of a dry spell in the bedroom, cut a long story short, me her and a friend of hers all ended up in bed together. We all continued to see eachother since then and her friend has become commited to us and moved in last week, we are all getting on great but I am concerned about possible jealousy, does any in a similar situation have any advice on this?