What would you do?? (online date/escort site)?

I got my man of 3years this lap-top I pay $38 a month though Rent-A-Center it was for a sweetiest day gift (Michigan holiday) and from time to time I use it myself well my "man" has google as my homepage, well I was looking up a name of a song that sarts with a "B" the google seggestions poped up and under that search history as well poped up (which I never noticed before) and things like "latian Booty" "Booty shaking" "Bouncing ***" poped up under search history now after curtis goes online he always deletes his today-history which I didnt really care I do the same thing. but then as I typed in the world REAL ad's from back page ang craigslist escorts and personal ad's women seeking men poped up so I started typing in words like Sexy, Juicey, Sex...ect and over 89 links poped up when I opened then it was from areas located around where we live and a city in another state which he was living in a few months before we got together. I was hurt so I called him and asked him he told me that it wasnt him and it must of been somebody who used the lap-top BUT YET nobody used it here and it hasnt left the house and he is on it everyday. I work mednights so now I really dont know if he creeps at night or not but during the day he is pretty much gone and hardly answers his phone and he is fast to get off the phone if he does answer. he doesnt like to go out with me maybe in the whole past 3 years we been out together 6 times. he wont kiss me he got me a sex toy and told me he cant handle my sex drive that he is getting to old (13 years apart) we hardly have sex anymore, he hardly holds me, hugs me, kisses me, talks to me he has a problem if i sleep in our room the nights i dont work so the past 5 months i been sleeping on the sofa in the livingroom. i cant touch or look at his phone he has a secret email/facebook and god knows what else.... i believe in my heart he cheated-cheating on me but I guess he aint man engouh to tell me. I been 100% faithful and honest to him but yet he tells me I ******/sucked his uncle and cousin and I got a gun to my head and a black eye for it even tho I never cheated he thinks I am a hoe he tells me im now the family whore (crying that hurts so much). I really love this man but he is nothing of what he was when I 1st met him. I dont know what to do I want to leave but its hard to walk away. I am in love with him but dispite what he says I know he doesnt love me. I been here for him 100% as well his mama, when she needs to go to the store or the doctors it me there, when he was in jail i was over there checking on her and helping her out. i just hurt so bad but i find it so hard to just walk out the door. ladys please help me here. funny thing is as I was typing in the words and finding all these site I seen he was also looking up enggaement-rinds / wedding-rings so that really hurt cuz if he asked i would of said yes and yet he plays me, dogs me and mistreats me. i bend over backwards for him and put him b4 me as he once upon a time did 4 me and my son but he dont do that anymore he turned heartless on me and broke my heart at this momment i dont even wanna live i just wont do that to my son but thats how i feel like just endding it.... he is the only man i ever let in 100% been right to 100% been right by 100% and been down for though the good and bad. i done fount condoms which we dont use, phone numbers, text, emails, people i dont even know called my phone with thier number blocked and he said YOUR MAN IS CHEATING ON YOU, ASK HIM WHO MELISA IS. YOUR A GOOD WOMAN HE IS NO GOOD then hung up, my man was setting next to me so I asked him and he acted clueless so i fiugred it was ppl playing on my phone well shortly after he want to jail for 7months and i fount a card in the car from a std testing center with his name a the date of a few days after his birthday. then i fount melisa's number as well other numbers..... ladys please help me because i feel so weak when it comes to him, i know i sound foolish and dumb for staying I NEED HELP letting go of the man i love