Intention or impact? Which matters more?

Sorry guys, this is going to be a long one.

My boyfriend and I have been having some issues throughout the 1.5 year of our relationship. In the beginning, he was very shady about his phone. He claimed it was because he was embarrased that I might find his porn. To this day, he has gotten better about it and we both have free reign over eachother's phones and messages.

He has trouble distinguishing appropriate friend behaviors with girls. It first started with Mary. She was someone who really liked him before I came along, and according to his story, he never really liked her at all. She would ask him to hang out, he would say yes, then lie to her about something else coming up and having to cancel. She was extremely disrespectful towards me yet he still chose to entertain her (She fought with him and said stuff about me because he decided to go to my birthday party instead of hers.)

Then it was with Karen. My boyfriend doesn't have many friends, and he felt like he really connected with her because they both lived in Japan. She was an international student. They knew each other for a month and in the beginning, were texting every single day. After I mentioned it to him, they almost barely texted. One day, she was suicidal and had to be put into suicide watch. He literally broke down, saying it was his duty to make sure she was okay and that he was a terrible person (when in reality, if they never talked or hung out as he said, how would he have known she was suicidal and why does he feel responsible as if it's his duty). Additionally, he strongly encouraged her to go get "celebratory drinks" when she got out, and when she agreed, he said, "it's a date then!".

NOW there's Mia. I've briefly met Mia once before, and can tell that they are friends. One weekend, I was out of town so he came over to my place. He was feeling lonely and asked if he could have a friend come over and hang. I told him that it was fine, as long as I knew who it was. Then I find out that he had asked her to sleepover (in my bed I might mention) while he was drunk.

In all of these situations, I do believe that my boyfriend's intention were good and not to cheat. (I was skeptical about Karen though). We have talked about the implications of his actions and word choice multiple times and each time he brings up the fact that his intentions were not ill.

While I think intentions are important and I haven't disregarded his, I do think they aren't nearly as important as impact. Thoughts?