I called my boyfriend a loser because I was upset and because of my own low self esteem issues and
Insecurities. We have a very good bond. Needless to say, he's very upset and said he needs "some time." Will he come back?

Say your sorry and say exactly what you said in your post,then give him time to think.

That's all you can do for now.

You're right, thank you. It was just a bad mistake on my part, you know?

He might this time after he cools off, but one day may get tired of being called names, and leave, and not come back. Just so you know.

If he really loved u and has a heart he won't leave for good..
Hopefully he has "forgivness" in him

I did the same thing last night, and I feel horrible about it. He even cried, I apologized over and over, couldn't sleep and have cried about it several times. How can we say this to the person that we love? I don't know how to make up for it.