Just need to vent

So I've been off & on with this guy for 7 years but since January its become more serious than ever ups and downs & everything but he chooses to seek other women (which her denies) while I'm committed to him I'm ready to go our separate ways at times because he cannot admit to any wrong doing & it doesn't seem like he's gonna change & when I say I want to separate things get completely out of hand I just don't know what to do at this point