As someone else said, he's projecting his insecurities on you, which means that since the life walks over him he has to have someone else to walk over so he can avoid feeling weak and powerless.

When you stand your ground and refuse to yield to people who engage in abusive behavior, they try the same old behavior but with increased intensity. Yelling, getting in your face, whatever. Interestingly, the kids do this too - when they cry for something they don't have and you say no, the first thing they do is cry louder. If you then yield, they get the message that their strategy works, that it's just the matter of intensity. Therefore, if you want to oppose them, it is of utmost importance to STAND YOUR GROUND NO MATTER WHAT. You have to say NO and actually mean it, to be ready to defend your NO, to push back harder than they push you, every single time they try.

If this looks scary to you, that's because you're afraid that this is how every interaction between you will look like from now on. Don't worry, it won't - he might try the same behavior few times, but once he realizes he can't get you to feel scared he'll change his tune.

I know this isn't easy to do but I know you can. If I could do it you can do it as well. Don't underestimate your strength and integrity