I had a christian boyfriend and he broke up wit me because he's religion. I'm catholic and is he allowed to be with me or no?

How old are you? Sounds like pressure from the parents more than the guys feelings.

Some denominations do not view Catholics as Christians, some go as for to say they worship the anti christ. So if they belong to one of those groups, their parents may be stopping it.

Sounds like parental pressure to me too. Fr_Chuck's right, certain denominations do not think kindly of Catholics. To them Catholics are as good as pagans. Not worthy to be called Christians.

Any prohibition of ANYONE against dating anyone else over religious or cultural reasons is a personal decision based on their personal beliefs. Yes, their religious or cultural upbringing might prohibit them from dating outside their own religious/cultural sphere, but there is nothing else that prohibits it.