Major anxiety problems about my relationship

I've been with my boyfriend for almost a year now and things have been fantastic. We are soon going to be moving in together. He treats me great and he's just overall perfect for me. But that's the problem, I'm so terrified that things are "too good to be true", that I have anxieties about the possibility of underlying problems. I'm terrified that he will find someone better than me. (If you couldn't tell, I already have low-enough self esteem).
I've had a few exes dump me out of the blue. One second they are describing their never-ending love for me, and the next day they dump me...for no valid reason. I'm so scared of this happening to me in this relationship. This is the best man I've ever been with but my stomach is churning because I'm bracing myself for him to dump me.
I don't know what to do. There is nothing wrong in our relationship. But its like I'm PUTTING problems in it....and I can't stop myself. My anxiety could be the demise of the relationship, so why can't I stop it?

You can stop thinking of past boyfriends and think of him here and now , the energies you let off and the things you say make you too clingy.men want a woman that can be strong but pliable too.Nothing is more off putting then that damsel in distress routine.Would you want a guy with your self esteem issues ?
If no then work on it its easier said than done but if you dont try you dont want to get better research self esteem issues on the internet and take what applies to you from the info and work with it.Dont become that to hard to approach woman either, find a happy medium remember he fell in love with you not your ex baggage.
Dont invent problems life will give you enough of them to keep you busy.Good luck to you.

Do you have evidence that he is going to dump you like your last boyfriends? No? Well stop acting like he is like your other boyfriends. Your other boyfriends probably had their reason for dumping you. They waited until they found another girl, then dumped you because of your insecurities.

"Fake it until you make it" means act confident until you feel confident.

If you have a true anxiety disorder, maybe meds will help you. Or sometimes you need to know how to find better men.

It's easy to say 'forget about what has happened in the past' so l won't, although it'd be a good place to start.

If everything is great, then embrace it, enjoy it, and appreciate it whilst you can.

You say you have no reason to be insecure or worry - don't allow that insecurity to become a barrier or itself become an issue.

If things between the two of you are as good as you say, then maybe talking to him about it might help?

I am wondering if your extremely low self-esteem might be part of the reason why you have experienced heartbreak in the past... I have found that people with very low self-esteem can be draining to other people.

I would suggest this - talk to him and let him know your worries and concerns, but don't do it in any accusatory fashion. If things are as good as you day and he hasn't done anything wrong, then he may see this as either clingy or telling him he isn't doing things "right" for you or something.

But more importantly, you need to concentrate on being happy yourself and realizing that you don't need to have such low self-esteem. Obviously you have been in relationships before and are capable of maintaining a very good one (your current one), so what is so bad about you? The answer - nothing.

And, depending on the severity of your self-hate, it might not be the worst thing to look into talking to a counselor or something.

Good luck.