Nuvaring

So I'm on the nuvaring and my boyfriend has been coming in me . we have sex like 3 times a day. I haven't had a period since Ive been on nuvaring but when I take it out there is a small amount of discharge looking blood on the ring. How well does nuvaring work? I'm not freaking out or anything because we live together and he very well takes care of me. But I'm just curious .