This is going to be a long one. I believe that knowing some main details is important for anyone to understand the situation. I would really appreciate it if anyone can advise me how to stop thinking of this situation day and night for the past 3 days.

In this 4 years relationship, the happy times lasted for 2 years and for the past 2 years things have not been good. We have stayed under one roof for about 3 years but I have my own place for about a year now, but I do stay at his place for most of the week.

Lots of fighting, arguments, then patching things up, believe each other that although we are not getting along, we still love each other and are going to try to hold on to this. But actually the truth was that we should not have been together when things started getting worse. We basically stayed like a husband and wife that felt that breaking the marriage is not the best solution but instead trying to make thing work is. However, I was never satisfied with how he tried to make things work. He just thing he never did his best. Never made time for our relationship although knowing its not good.

I have told him several times that I want to leave him but he says that he loves me too much to let me go. So he would never agree for me to break up with him. The only ways that I could have left him was by just disappearing from his life without any trace or maybe found a new boyfriend. But I couldn't do either. So we dragged our last two years of fights, abusing each other, shouting and then trying to sort it out.

A few days ago, his friend told me that he he likes to be with prostitutes. His friend was almost involve in it because he wanted to call escorts to his place while his friend was there but his friend did not wanted to do this. Besides this thing that his friend knows, he said he went to a strip club with him and my boyfriend has told him that he has been with a prostitute a year ago, six month ago and a month ago. Besides this he does not have any other evidence. I am even to a 100% sure whether he is actually doing this because I know my boyfriend can be a person that likes to boast to his friends. Maybe he is boasting about all that to shows something to his friends? Or maybe I'm just thinking too good of him again. I do believe his friend, but at the same time I will never believe it until I know someone or have seen something that proves that he is doing this.

He had made me believe that he would never do anything with a hooker but rather with a random girl from the club. So that's why I am in a shock. I can't stop thinking about it. For 3 days I have forced myself to sleep for a couple of hours a day and from the time I get up to when I fall asleep I keep thinking of the same thing. I want to find a solution to my situation that is that I first need prove he is been doing this or catch him doing this and then I want to confront him. I want to tell him that I know what he has been doing and that's why I am breaking up with you, but the friend that told me about this truth doesn't want me to to tell him that I know that because apparently he is the only person that knows that. If that is true then he will never talk to the friend again and I don't think I can break their friendship like that. I can't be bad to the person who helped me open my eyes. But also I can't carry on with this relationship or end this without confronting him.

I have this strong urge tell him that I know. I just want to talk to him about this, I want to hear his reasons I just be quiet about this. Its driving me crazy. I also need to stop thinking about it. How should convince myself to not think about it every second? I need to get work done. I need my concentration. I need to take a break but I can't just run away. So what should I do? What is the solution to this? How should I decide what I want to do?

(An ascot is a scarf worn around the neck and tucked into the top of an open shirt. You mean escort.)
This isn't about him. This is about your fear of leaving him. You should have left a long time ago. "So he would never agree for me to break up with him" is classic passive talk.
You have your own apartment. You aren't tied by children, or lack of money.
LEAVE and don't look back! Who cares if it's 'random girls from the club' vs hookers? Why do you feel a need to confront him? What good will that do? He'll make excuses and promises and sweet talk you, and you will cave in again. He does this because he CAN.
If you want to talk about why you can't get out of your slave mentality, please answer below.
Usually it's because of not feeling good enough, lack of confidence, and so on... low self-esteem.

The only ways that I could have left him was by just disappearing from his life without any trace or maybe found a new boyfriend. But I couldn't do either. So we dragged our last two years of fights, abusing each other, shouting and then trying to sort it out.

You already have your solution. You just have to do it and top talking to yourself and tripping over your own fear, and he doesn't have to agree to let you go. That's a lame excuse to stay in misery.

You are making excuses. You say that it's been bad for years now but he won't let you break up with him. You don't need permission to break up with him... just do it and live for yourself. Why you feel the need to confront him about anything is beyond me... just break it off... don't ask, do.

Thanks joypulv, talaniman and odinn7 for reading and the replies.

The reason I said that 'he didn't agree to it' meant that he is not leaving me alone. I would have got over him if he didn't keep coming around and convincing me how much he loves me. I also know that there are many other way to make sure he doesn't contact me but I never hold it together for long enough. I always end up talking to him.This is the first serious and long relationship I have had and I just feel that I had to try to work out things because there never was such an extreme thing that I found out about him until this time.

I do really feel the need to confront him because all these years I have told him everything and I want to let him know that I know you are doing these thing. I know you are not the person you told me you are. All the swears that you took upon your parent and god are fake. That's also the reason I want more prove that this is definitely happening. I want to feel relieved. I can't hold it all inside of me. And I don't know how I would be able to do all this. How can I catch him? How do I tell him I know all this? Also I do not want to cause trouble to his friend if he has told me the truth to help me out.

(p.s. I feel that his friend likes me but I really don't believe that he would lie about all this to just break us up)

OK, this is different - sort of. You don't have PROOF. His friend likes you. He might be making it all up; he might not.
Never ever believe someone else without proof, and yes, the friend might be lying because he likes you.
You owe nothing to the friend. He is the one causing trouble. If he is such a good friend to your boyfriend, he wouldn't be telling you these things, true or not.

But I say 'sort of' because you have been fighting for years and you have tried to break up for other reasons. AND you are the one who said he told you he wouldn't go to prostitutes, only random girls from the club. Isn't that bad enough? What's the difference? Cheating is cheating. I suspect that a lot of your fighting was over how much time he spends with you? He sounds like a man who wants his little sweet woman waiting for him while he goes out and fools around. Do you fight over where he is, why he isn't with you?

Break up with him regardless of proof about hookers. You probably will never know.
If it's killing you, then confront both of them when they are together. Yes, it may ruin their friendship, but the friend opened that door by confiding in you.

I came here with all intentions and I think this is the best way that I can. Myself and my partner have had ups and downs and it is hard but working through things is best. I could never give up without knowing I at least tried but at the end of the day if you have decided it's not working after that then you should leave. It's not a case of whether he gives you permission to, it is not fair on either of you to stay. Plus if you are abusing each other as you say then it sounds to me like the further away from each other you get the better, your relationship sounds toxic.