Usually prepositions depend on the verb, so I would recommend learning the prepositions that are used with each verb. Now, there are verbs that may use more than one preposition. For example: I am doing this for her. I am doing this to her. In this case, the main difference is that "to" identifies the object of an action, whereas "for" identifies the beneficiary of the action. I am doing this for her (彼女のために). I am doing this to her (彼女に). I am doing this to her for you (私は彼女にあなたのためにこれをしているんです). I hope this helps you.

'for' is the usual preposition to connect a 'too..' phrase to a noun eg It's too expensive for me 'to' usually connects a 'too...' phrase to a verb. So the phrase 'too much to a man' doesn't sound quite right - I'd stick with the first one. eg it's too expensive to buy