Relationship problems. Help

Okay so i just turned 18 & my boyfriend for a year is 21. He has a two month old son with a one night stand girl before me and him began dating. They have no feelings for eachother from what he tells me. I believe she has feelings for him but i'm not really worried about it because she isnt his type but our real problem is when ever i try to tell him how i feel he gets angry at me and makes me feel like the bad guy. I would like to know how to fix our problems. I'm always trying to hold in my feelings now. I wanna be able to talk to him without arguing. I want to make our relationship work but if it keeps going on like this i don't know how much longer i can put up with it.

He needs to admit that he is part of the problem. If he can't face that then you need to leave him. This can only work if both of you are putting an effort forward. If you're trying and he's not it will never work. Do what you have to do to achieve your own happiness. Remember their are always oportunities with other guys. Don't wait until you've got a couple of kids with him because that's going to make things worse, not better. Sit him down and tell him one more time and if he tries to make you out to be the bad guy. Get up and walk out the door. Trust me you'll be better off.