Is it worse if your bf cheated after you started dating or just had a person on the side?

Cheating is cheating. If you accept this, then you will be disrespected even worse. You deserve better. That was deceitful. How could you ever trust him again? Find a man that has moral values. If this guy is willing to use this woman, he is probably capable of a lot of other immoral or even unlawful things. Pure and simple, it means that he has no regard for other person's feelings. He only cares about what satisfies him, regardless of disrespecting or hurting others.