My mom's boyfriend is making me mad and I dont know why ?

my mom is starting to date and the guy is really cool and fun , but whenever I see them together I get soo ANGRY!!!!! Like I wanna break somethin, ecspically when I hear them laughing in her room! I then snap and loose it. Whenever hes around my moms friendds he likes to show off by gettin drunk, and smokin, I once saw him try to play with my mom by puttin a ciggerte in her mouth and I know she smokes but I really want her to stop and hes not a good influence and when im not around they act like a couple and be all touchy and I get Angryyyyyy! Like I wanna beat somethin up! He acts nice when its just me and him but somethin about him being with my mom causes me to lash put and it seems like he is all she thinks about n when im around her she is always in a leave me alone mood but when hes with her she want to be actin all nice like she wants to do stuff...someone help me! And I dont want to tlkk to her about it because she will get mad!