yep, i do this for yc!
just like the rest of yc, taking care of yourself and your cofounder relationship is DIY but we offers resources to help. i'm an executive coach (with a specialty in startup founders) and our founders book office hours with me when they need support around managing stress/anxiety, troubleshooting conflict in difficult relationships (with cofounders, investors, loved ones, etc), communicating effectively, and generally thriving on the roller coaster of startup founderdom.
i also provide referrals to therapists and coaches when necessary. it depends on what the founder's looking for and what they need.
i'm happy to answer any other questions you have about this.