Should I wait until I sleep with him???

I've been seeing this boy for 2 months. He genuinely cares for me and puts in a lot of effort to show his affection. I have a rule of not sleeping with boys until we are official because I know once I have slept with them I will instantly fall for them. There have been times when it's so close to happening and basically I can't wait any longer to sleep with him!!!! 
I know that I'm a few more weeks we will be official and in a relationship. Should I get some will power and resist the urge or just go for it????