Why την and τον and not της and του? Sorry if that's a dumb question
Because they are the direct object of the verb "love", not the indirect object.
is it incorrect to say αγαπα τον;
Yes. You can say αγαπά τον άντρα (when followed by noun), but pronouns come before the verb: τον αγαπά.
Why is και incorrect?
Και is not incorrect, it is in fact part of the answer, as shown above. Unless you copy and paste what you wrote in your comment or provide a screenshot, there's no way of telling what might have gone wrong, as your comment implies.
Is it necessary to put επίσης at the end? I put it after γυναίκα , but it was wrong.
Isn't "τον αγαπα" redundant here given the reciprocity inherent to "επίσης" so that "Ο άντρας την αγαπά και η γυναίκα επίσης" is correct?
«αγαπά» sounds wrong - more like "aga-guh"
It sounds clear to me, on the web.