Is this normal? I need opinions.

I've been with my SO for 3 years. During this time we've had plenty of bad/good times. He will get angry at me over the littlest of things, call me a cunt, say I'm useless calls me a fuckhead blah blah. Actually last night he didn't think I locked the door properly, I told him to check if he doesn't believe me. His reply was 'I don't care it won't be me who gets raped ' We move on from it though and end up being all good. Anyway I have appoitments once a week, but I have a crush on this guy. It's hard to explain. I love my significant other so so much but when he treats me like this, it's so easy to get butterflies when someone is overly nice to me. I wouldn't do anything to hurt my man, I just have no idea why I'm feeling this way towards someone else while I'm in a relationship!!