You have certainly heard numerous justifications offered from various people for why they do what they do: “It’s what my dad/mom always taught me to do”; “It’s what felt right at the moment”; “It’s what my husband/wife told me to do”; “I have a right to be happy and do what I want”; etc. You, no 
doubt, have heard some real whoppers over the years.
One explanation that is commonly made goes something like this: “I understand what you’re saying, but I believe God wants me to be happy.” Or, “I’ve spent a lot of time thinking about this, and there’s no doubt in my mind that Jesus wants me to do this.”
If someone says this to you to explain an action, let me give you a simple (and politely-toned) thing to say: “How do you know?” There is only one way we know what God wants us to do and that’s in the Bible. The only way to be able to justifiably claim God’s approval (“God wants me to…”) is to be able to show authority for it in the Bible (cf. Col. 3:17). So, can it be said, “God wants me to…,” or should it be, “I want me to…”? Something to think about.