Ahhh.... here is the ultimate decision... When you play in this arena, you must have rules set out.
There is no room for jealousy in any sort of "open" life style. Jealousy will destroy your marriage (relationship) in that sort of fertile ground. That being said...
Talk it over with your partner, get down any restrictions they may have, any restrictions you may have... if something doesn't feel right... stop...
If you do go through with it... discuss it openly. Remember that it is still your partner's right to say that they do not like it... but it is pandora's box. Once you open the box leading to an alternative lifestyle... it could be hard, if not impossible to shut.
Just talk to your partner a great deal... perhaps you should start off with some light petting and make out sessions... maybe get involved with swinger groups in your area... there are some that are very respectful to those that are new, and not sure if it is what they want.
Just some things to think about...
Good luck...
The Dreadful Muse