Is it possibly just a bit of FOMO since you didn't get those experiences you feel almost build you up as a person?

That being said, I feel you should communicate this to your partner that the past experiences didn't really satisfy you as much because of your lack of interest so maybe you can have an experience with someone who you didn't feel wasted your time. I'm sure he'd understand if you two have already branched out but just be cautious to adhere to your partner's wishes too so you know neither of you are being neglected in some way.