I want to cheat

Ok .. so I want to cheat on my partner of 5 years. But please here me out.
We were each other's first sexual partners, (sex) and that was something that was special to me. We got together at 15 years of age. This is where it gets difficult. 6 months into our relationship he broke it off with me and within a week was sleeping with his "new girlfriend" within 4 months we were back together and everything was ok we had worked everything out. 3 years later he cheated on me but he didn't tell me for 6 months as he thought I would leave. I had a feeling he had cheated but I trusted him so I did Persue anything, I kept on hearing stories and eventually I asked the lady in question 6 months later and she admitted it and that's where it all started, anyway long story short we have now been together for nearly 6 years, and I have forgiven him and I want to spend the rest of my life with him I want to marry him and I love him with all my heart. But now I feel like we don't have that special connection that we first had being each other's first as he has experienced other sexual
Partners, and it's something I feel like I need to do just once and then I can carry on living my life with him. If I did persue my fantasy, I know exactly who I would with, someone that I once have had a connection with before ( never got as far as sex) and it would just be once.

But I know my partner would never allow it as he does get abit jealous with this particular person.

I want to be with my partner but if I don't experience it once with someone else I feel like now I will never really be satisfied because he has been able to get the best of both worlds, cheat and still comeback to the one he really wants. I know he will never ever ever do it again as we have worked with each other very closer within the last 2-3 years to get where we are today. But it's just this holding me back.

Is this so wrong of me?

Please help me now.

Lela