“Rommel was largely apolitical. His involvement in the July 20 bomb plot was never really proved and he took the out Hitler gave him simply to spare his wife and son the wrath of the SS.”
Aside from his family Rommel was a soldier first and last. Without doubt he took the cyanide to save his family from certain death.
Rommel also had a policy of “war without hate”. He was known for honorable treatment of prisoners of war. In the North Africa campaigns he used Italian troops to guard POW’s whenever possible so he could have as many German troops on the front as possible and he was assured the Italians wouldn’t mistreat the POW’s.
As to the bomb plot his COS Hans Speidel was in it up to his eyes. I have read speculation that Speidel implicated Rommel in order to save his own life. That implication was enough for Bormann, Himmler and especially Goering to call for Rommels death.