Is it normal to let my boyfriend sleep over all the time?

I am a female in college and I live in a house with 2 other girls I've known for a while. I am the only one with a boyfriend, who I've been dating for just under 2 years and he is also good friends with the two girls. We both have the same major at the same college and therefore spend most of our day on campus studying. After studying late, he usually comes and sleeps over almost every day as it is a 5 minute walk to campus as opposed to his 30 minute drive home. We all have our own individual rooms and there isn't a living room so he just comes into my room and we sleep. This has been going on for 5 months now and my roommates have not said anything about it until recently. Recently they called a house meeting and in a very rehearsed manner proceeded to ask me if my boyfriend lived here and then suggested he should help pay THEM for rent/utilities even though most utilities are covered by our landlord. The only utilities we pay are wifi and electricity, and neither goes up because of him. The wifi stays the same and I'm using the lamp in my room whether he is there or not. We are both aware that he spends a lot of time here so that's why he tends to buy food for both my roommates and refuse when they offer him money. He also buys house goods, such as toilet paper and paper towels for the house without anyone asking him. We both agree that he is over a lot and should help out, but buying them meals every now and then and goods for the house seemed to be sufficient. Is it normal for a girlfriend to let her boyfriend sleep over all the time without contributing to rent?

I never thought it would be an issue, but them brining it up has me doubting myself if it's okay to have my boyfriend over all the time.