Should I call it quits? How does a gal deal when she finds LOADS of on her man's computer?

By loads I mean 200+ movies and just as many pictures. We have on a regular basis, and he doesn't seem dissatisfied with me. The isn't a big deal, but when I have asked him before if he uses to "do his thang", he has said "Nah... I've never really been into . I usually just think about you". I've found pics before of a girl's that he was talking to on myspace, and became OUTRAGED (hence the repeat snooping offense on my part). Yes, we have trust issues, and this is probably not the most healthy relationship... which is why I am reaching out to you. We've been together nearly 3 years, and in this time he 1). hasn't shown any financial responsability (not saving money, buying things he doesn't already have the money for, etc)... 2). hasn't shown any ability to improve his sloppy habits (leaving trash on the floor in the house instead of the trashcan, not putting his ONE dish in the dishwasher after I cook him a large dinner and clean the kitchen, stuff like that)... 3). not defended me when his family yells at me (for stupid stuff, like parking the car in the driveway?... yeah). I'm about fed up with him. But the thing is, despite all this, he is my best (maybe only TRUE) friend. After finding all this on his computer... I am really upset that he lied to me about it (I truly wouldn't have cared, and probably would have suggested we watch it together) and tried to humor me with his lies. I'm tempted to gather all my stuff from his house and not talk to him for a long time. I want to leave the huge list of files (with thumbnails) up on his computer with a post-it that says "have fun with your broads, hope you made the right decision" on it. GRRRR. I won't do it, but that's about how fed up with him I am. How can I handle this situation? Thanks in advance.