I am in somewhat of a poly relationship right now, I am not going to go into detail about it as it gets a bit complicated and confusing at times, but for now it works well for me.

I have no issues with playing or sharing with others. I won't lie and say I haven't felt the twinges of jealousy either, because I have. I work through those feelings and sort them out on my own. If I don't then the relationship has failed for me, and I must move on.

It all depends on how you can deal and handle the feelings you will undoubtably have.
Can you deal with jealousy? Can you equally share feelings and affections with another?
It's how you deal with these things that will determine how the relationship will be affected.