2. If your Boyfriend is bringing them up, it's time to talk. Tell him how hurtful it is when he mentions his ex and give him a chance to change. If you see no improvement, you should re-consider your relationship. He may not be over his ex.
3.If you're thinking about them yourself, look at why. Is your self-esteem not as great as it should be? This may well cause you to be look at his past relationships and cause you further worry. Perhaps you are a jealous person? Whatever the reason, only you can work it out.
4. Live in the moment! Those past relationships didn't work for a reason.