Heart has to belong to One

All my life i've been playing it up with a bit of sexual actions. I don't exactly know how it started, well i do, but i don't know how it kept on going. Everywhere i turn there is something sexual-related in view. And then i meet the most amazing guy ever, and all i want is for it all to go away. I want to be is perfect girl, 'cuz i know he is my perfect man. He's honestly everything i could ever ask for. He's got a brain (which men tend to lack), he's adorably cute, funny, and then he can be mature when the time is right, but he can also be very immature. For his twenty-two years of age, his mentality is basically of a twelve year old. But i love it, he's really great.
Then there's me.. i do these weird things subconsciously, without knowing i'm doing it. Like i was talking to an old friend about one of my fantasies, which is quite embarrassing to state it on here. Anyway, he was so interested and said he'd want to be there to see whenever my fantasy would occur. I told him he's allowed to be there because my boyfriend isn't interested in my pleasurable dream. I told Paul (my boyfriend) the whole conversation with my friend, and he then became very upset that i allowed another man to know what i want to do, and even let him see. I felt i was just joking with my friend who lives all the way in Alberta, Canada. But Paul felt hurt, and honestly it pained me to have made his heart swell up in agony.
One of my biggest fears is hurting my baby, and that's what i am pretty good at doing. 'Cuz i've got many friends who know about how i am. And we talk freely, never thinking i have a barrier to stay behind. I do now though. Yet, how do i remind myself to put up boarders around every man i talk to?

I'm afraid i'll become somewhat unfaithful towards Paul, and hurt his feelings. Although i'd never ever physically be with another man. All i do is talk, or rather type.. not even talk. So then how do i stay put with one man when all my best male friends know me as someone really open and frank?