First, let's dispense with one of the most common misperceptions.
Poly is NOT about SEX - only peripherally.
Sex is about sex.
Don't confuse the two even though they may ride side by side.
On one hand, you are lucky, being the female of the couple. Your options for fulfilling all your sexual needs & fantasies are pretty much unlimited. And it can be done in a variety of safe ways. So that's the easy part.
You can explore swinging, find a FWB situation etc. And who knows, your SO may get some thrill from knowing or watching you be satisfied. It really can be a very bonding experience. It can be like a gift he is giving you. Trust me - it works that way
Poly, on the other hand is something you need to educate (both of you) yourselves on. Because it's very difficult for many people to separate sex and emotional bonding. It's then that you both have to be prepared to have the "poly discussion". You may not feel the necessity in the beginning but if you launch into friendly sex there's a good chance you may find yourself there.
Better to see it coming and have some plan in place to deal with it intelligently.
If it never happens - fine. But there's a reason most ships carry lifeboats that are never used.
Don't confuse apples & oranges. Do some thinking and LOTS of talking first - then go for it. An unsatisfied (sexually) partner in a relationship is a time bomb. There's plenty of safe ways to diffuse it.