Pls help me im really depressed i need some advice on my relationship?

ok i been with my bf for 3yrs now i was 17 he was 21.. so in the beggining of da relationship i cheated on him a few times but not to hurt him but also not to hurt myself cuz in my past relationships ive been cheated on lots of times.. so when i first got with my bf i didnt really think he would take me seriosly like the boys i dated in the past. i was single for about a year or less before i got with him an yesss i did my thing but not how ppl said i did.. so anyway i didnt think he liked me or wanted to be with me as much as i thought an for the fact at the start he did act a little like my past bf's as in not beinging home when we planned to hang out for that day or he would have his guys over an having his sister tell me that hes in his room with his frnds... i still had my guy friends that i was talking to when i was single yea some had benifitts an some were just frnds and so i kept them as a secrete soon things started getting better between us i started to see how he really was an i liked it i liked the feeling he gave me but still deep dwn i jst have gavin up on ''love'' so now in total its been 6 mnths an things started getting obvious cuz i was still talking to the boys an ppl been telling him things about me since we first hooked up an how i been around an all these lies but little did i know my own best friend was the main reason why he started to believe the rumors an when i say i cheated i dont mean that i had with anyone its more like i hung out an made out with guys that liked me an wanted to date me but were not my bf material type... he kept telling me he nver believed it untill my frnd told him things about how i slepted with these other guys an if she was him she would not dare to kiss me or even waist time on a girl that cheats... the fact is that i knew she kinda liked him but really shes not his type but they wer frnds only cuz she was telling him all these things he wanted to hear.. half the stuff she said was true which is about the (3boys) an the rest was mind games she was trying to see if he would do more then jst lean on her shoulder an ask why an all this stuff about me... so i stopped talking to her an he begain to not trust me but i knew he still wanted me really bad an he would leave me then call me an say he doesnt care what they say he still wants 2b with me so a year pes by an he doesnt trust me but he still loves me. So our relationship kinda went sour but not to the point where we can no longer be together.. he seems to hold on to what ive done an likes to acuse me alot an throw things in my face an ask alot of questions i understand that i sort of desereve that kind of treat ment but really its not my fault i didnt have my heart in the right place it kinda felt like my past was making up my mind an was the reasons for my actions... so thats the reason why till this day he holds on to it more then he holds on to me we always argue i dnt understand why he still hasnt cheated on me or so i think he hasnt an it kills me inside to think why why why??? an when i acuse him he jst tells me ohhh im not u im not a cheater... i dnt understand how come karma hasnt made him pull a trick out his sleeve yet??? for 3yrs now we been on an off i really love him but now iim starting to realize he doesnt love me as much he never tells me but he does kinda show me but in the poorest ways he keeps me in the middle an jst pulls my strings i feel so much guilt inside so i jst keep letting hiim pull an pull an make me dance like if i was a his own personal puppet! its like im trying to make him see that im sorry an im not the girl that i was before an i forgot to mention trew out 1ina half yrs i did talk to boys but not the same ones from the start soooo itsbad enough dat my bff had it in his head i was no good &i dont get treated equily he went to texas for a few mnths an again rumors start to pop up i dnt kno why an how but it messed up everything for good he started talking to this girl he would tell me about her but only things that wouldnt get me mad so i didnt really mind i trusted him so the rumors got to him an im sure he tought of the past an said to himself this girl is doing something so he broke up with me an kinda started a fling with this chick again we got back together i didnt know about them untill he got back he told she like him alot an he liked her.. they had an all he said she w beggining to become a lil to much like his gf she wud see if was talking to girls an she would get cranky when he did talk to girls ohh they worked at the same factory as why im saying she watched over him like that so he came bak to chicago an we started out really bad an argueing as you can tell thats what we do alot :/ so now as in today when we argue he tells me he doesnt want me but he still calls me over an still shows love an we are dating even if we brk up or i storm out the house i kno i can always go bak but im tierd of beggingg him!!! i love him but i