How to say grammatically "something which if it matters.."?

I'd like to say things in this way, is it proper? For example

He went to see her which I don't know if was the the right thing to do..

Is it right? If false what makes it so? How can I express the same thing the most conscience way?

Thank you..

The phrase could make sense, but it is lacking punctuation, and has a few grammatical errors.

It would be, "He went to see her, but I don't know if it was the right thing to do."

Hope that helps.