no, benefits paid to you as a spouse will not decrease your spouse's retirement benefit. In fact, the value of the benefits you can receive, added to your benefits, can help your spouse decide whether taking benefits earlier may be more advantageous.
By applying, do I qualify if my spouse is already receiving benefits when I submit the application?
no problem if you and your spouse apply at the same time, we will also check your eligibility for spouse benefits. If you qualify, your application will automatically serve as a request for spousal benefits.