Tell all of the other parties that you’ve made your final decision. Thank them for the negotiation. If you did it well, they’ll usually thank you back, tell you to keep in touch, and to reach out again in a couple years next time you’re on the market.
“Hi Joel, I’ve been thinking it over and it’s genuinely a really tough decision for me. I loved everyone at [COMPANY] but the one thing that makes it hard for me is the salary. As you know I’m trying to pay off my student loans so salary is really important to me right now. If you can improve the salary by 10K a year, then I’ll be totally ready to sign.”