I don't know why I'm so nervous about it I offered him to move in with me and my bf and we haven't discussed him paying rent. How would you word it? "So hey, I was thinking 300 a month".. it sounds so rough to me. Help

*I know I should've discussed it in the beginning. It was kind of like a "well if you ever need a place to stay, we have an extra bedroom" and he took us up on the offer. Hes in his 30s and all my siblings make about $6-12 an hr more than me so 300 shouldn't be too much we pay 900 a month not including food, water, dte. So itd be split 300 amongst me him and my bf.