Incorrect spelling, explanation: blaimed is an incorrect rendition of the pronunciation of blamed. The pronunciation may suggest that there’s an i in the word, but if we think about it and about the principles of English grammar, the existence of this word would suggest that there is a base word such as to blaim. There is not, which is why only blame and blamed can be used correctly.

Correct spelling, explanation: blamed is a past participle of the verb to blame. In general, in English, the past tens (at least the regular forms) are derived by adding the suffix -ed to the end of the word. In this case, only d is added to blame = blamed, as there is already e at the end of the base word.

Definition of blamed:
Verb, past participle of to blame
1. To be judged guilty of doing something or responsible for a fault.
Everyone blamed the rain for difficult conditions on the road.
I felt blamed for not going to the school my parents wanted me to go to.