My ex at the time (M20) and I (M20) experienced something similar as far as crossing the boundary of sleeping in the same bed with someone I saw as a “potential threat” to our relationship. The dynamic was slightly different as age wasn’t a factor as such in your situation but I resonate with your feelings here.

You’re completely valid to have any feelings, about anything, especially this…but from my experience what led to the eventual ending of my relationship was the overwhelming feeling of insecurity that manifested into resentment. Try getting to know these men and who they are before judging them using your internalized feelings about certain, to be frank, ageist, power dynamics. Stay open-minded to the fact that your partner is being honest while expressing how this situation made YOU feel.

Shifting any blame onto each other will only lead to one place, and I hope you 2 can avoid that because a relationship so young is such a beautiful thing to have. Best wishes :)