I need to know about chlamydia?

I have been tested for chlamydia and i have it. Now i have been with my parter for over a year and about 6months ago we broke up and i did sleep wif someone else. Now the person i slept with we used a condom, Then me and my partner got back to gether and ever since we have been 2gether we have never used a condom. So i want to know is it possible i would have got it wen i had the one nite stand or is it more possible i have it frm my boy friend. Also if i did get it frm my boyfriend could i have had it for a while and not known or is it a std that u get pretty much straight away. If some one could answer my qu i would be so grateful.