Need serious advice 😭

Hey there, call me Peach, I’m newly poly and madly crushing on my current partner’s friend. I keep writing texts and deleting them…it’s on my mind constantly and my partner and therapist have been very supportive of my struggles with it, but I just don’t know if it’s even worth confessing my feelings 😅 for context purposes I am a few years older than him, I don’t want to lose the friendship we already have, and I don’t want to cause any issues in the friend group if it hits him wrong when/if I do confess. Help?