@missjena, the way you describe your situation implies a sense of helplessness with regards to this issue, as though the fear of being cheated on is something that you can’t control (e.g., “almost all men cheat”, that it’s “almost impossible” for you to feel better).
I think the first thing that you need to do is realise that you do have control over these feelings, and that your own mind is creating these anxieties and worries for you. Yes, you may have been cheated on in the past, and that may make you feel vulnerable, but your own thoughts on the matter are prolonging that pain longer than it needs to go on. Things have and will continue to happen to you that you cannot control, but you can control your reactions to those events, and ultimately, how big an impact those events have on your life. You need to deal with that yourself – this isn’t about your relationship now, or about your relationships in the future, it’s about you. Making these sorts of feelings a “relationship issue” rather than a “personal issue” pins your issues onto your partner and most of the time that happens, things turn sour. It just isn’t fair on the other person at all.
With regards to your question, you will find that people can identify with you, and will be able to identify with you. This will always be the case, as long as human beings are falliable creatures, prone to insecurity, able to speculate and hypothesise about abstract future events, and are endowed with cognitive abilities that can make or break us. It is natural to instinctively seek out like-minded people as a source of support and comfort. I think almost everyone can identify a sense of comfort from feeling like they aren’t alone with feelings they have and don’t like. However, I really don’t think this should be a long-term coping strategy for dealing with these sorts of feelings – other people may well have the same anxieties as you and you can gain comfort from this, but it doesn’t mean you shouldn’t do everything you can do move on from these feelings.
All of this can be more easily said than done, but with so many forms of negative, worrisome and ruminative thoughts, simply being able to exercise a degree of control over them and recognise what they are is hugely positive. Even if you can’t stop the thoughts coming for now, just being able to control them, and identify them as realistic or unrealistic, irrational or irrational, and understand where they are coming from, should help you a lot. I think this will apply far beyond your concerns about relationships and being cheated on, and so whilst I don’t think this sort of learning and growth is a quick fix, I believe it is something that could prove really valuable for the rest of your life.