Yes, it is likely that your boyfriend was suggesting that the relationship is over.
However, in telling you that he “won’t subject you to that anymore,” he was being very ambiguous.
This most likely means that he was just trying to scare you into thinking that the relationship is over.
You both just had a fight and both of your emotions were running high.
If he truly wanted the relationship to be over, he would have been a lot more expressive with his feelings and definitive with his words.
If the both of you have a healthy relationship, he is not going to give that up over one fight.
You have since apologized for calling him a douchebag and you should not apologize any further.
Doing so would only keep making him feel as though he is completely justified in not returning your messages.
This means that he could feel that much more emboldened to stretch the couple of days that you haven’t heard from him into weeks.
Try not to get stressed out over the fact that you haven’t heard from him in a couple of days.
Guys often impose a period of time away because they want to punish the girl in making her worry that the relationship is over.
However, as long as you do not initiate contact, there is a good chance that he will reestablish contact.