I'm not sure I should be going to see my friend's boyfriend without her.
Do you think your friend's boyfriend is attracted to you?
Yes, I want to know if he's honest with me.
If you really care about your friend , then you should let their relationship run its course. If the relationship ends, then you can consider dating him after your friend seems to be over him.
I'm going to fuck him with all my heart.
You shouldn't follow through on that thought. Think about how hurt your friend will be if they find out. You'll most likely lose her friendship over this.