I have been widowed twice, and am currently unmarried. I am currently receiving survivor benefits from my second husband, which I began taking at 63. If I switch to my first husbands survivor benefit-which most likely is larger (I am now 67 and we were married for 20 years) would they be decreased because I received early benefits from my second husband?
No. The entitlements are separate, and any reduction taken on the one record wouldn't carry over to your benefit rate on the other record.
If your benefit rate would be higher on your first husband's record, you'll want to file as soon as possible. Since you are already over full retirement age, your widow's rate won't get any higher if you delay filing.