Relationship and sex help

I have been in a relationship for 9 months, and I care for him deeply. Recently, however, I've been having more and more random thoughts about sleeping with other men. I have always liked sex rougher but he doesn't enjoy going too rough. We've talked about it and tried, but he just can't do it. I never thought that I valued sex so much but this is tearing me up. I know I love him, but this has become a serious problem to me. Does this make me a shitty person? If anyone could give me advice, I'd greatly appreciate it