My boyfreind and I have been living together for a year and he has two children, whom I have never met. This bothers me a lot, but I don't know how to talk to him about it or the real reason he does not bring them home. I know he loves me- what do I

This is difficult for both of you. There's probably a thousand reasons why your bf is reluctant to bring home his kids. He's probably worried sick that something will go wrong ie: you won't like them, they won;t like you, that it will ruin a good relationship allsorts of things might be going through his head ( all of them imaginary no doubt)
You need to tell him how you feel about his kids (you don't mention whether you want to meet them or not) and then take it from there. If he knows that you are looking forward to meeting them, maybe that would make things easier. Christmas is coming - maybe you could invite his kids over for an evening, tell them you have bought gifts? I just think that if your boyfriend knew that you wanted to meet his kids it might reassure him.

A year is along time that is 365 days, 52 weeks by this tme you should already know each other pretty good. Do you know if he has seen the kids lately? What does his family say about them? How old are they? I ask these questions to make you think? Please let me now I will try to help you if I can.

What I do not see in the question is if he sees them at all, but just not in your presence. If he sees them at all but keeps them away from you then perhaps he is wisely keeping his children separate from the love-honeys.
If he does not see them at all then either he is not being resposible with his fatherhood or he has decided it is in the children's best interests that the noncustodial parent (himself) not be some kind of hanger-on.
If all that is complicated, then accept that you picked a man with pre-existing kids. They were there first. It's not all about you. You have choices. They do not.

Maybe your boyfriend knows that his living with someone outside of marriage is not the role model he really wants to be for his kids.

TALK... communicate... hell write him a letter saying how you feel! sort it out with him. if you don't you will just make it harder on you both.

Wow, you're living with a guy and you can't talk to him about his kids? What's the rest of your relationship like? This should have been squared away before you shacked up.

You need to have a conversation and let him know how you feel & why you feel the way you do. Love has nothing to do with this.

Have you tried asking him in a direct but non-confrontational way? Something like "I'd like to know why you don't bring them home. It really bothers me..."?