Colleague keeps interrupting my classes

Hello, any advice you have would be greatly appreciated. I have a colleague who keeps coming into my classrooms and looming in the back of my classes. I have tried to give him subtle hints that he is not welcome. Asking him, “Can I do anything for you?” And saying, “I’ll catch up with you later.” Then he parks in the back of my classroom and just sits there, sometimes chiming into the lecture to tell stories about what I’m lecturing on. He constantly compares himself to me, which always results in him putting me down. I mentioned one of my classes wasn’t where they needed to be, and he asked if I wanted him to talk to my class. Um… no? He then said “Well I’m just louder, and you’re more quiet.” I told him we have different teaching styles, and that mine is working just fine for me. He has admitted to having impostor syndrome, which has slowly started to chip away at my work relationship with him because instead of just lifting himself up, which I support (“Yeah, you’re doing great dude”) he always turns anything positive he does into a comparison and puts me down. We used to co-teach in the same classroom, but he now just comes in to loom in my classes and it’s getting increasingly more disruptive. He asked me yesterday if he could come in and teach part of a lecture, which I initially said was fine but given the recent uptick in him just generally being awful towards me at every turn, I’m not going to have him teach that anymore, because I know it will turn into story time, and he will continue to put me down and erode away my boundaries. How do I deal with this? Is there one liner I can have canned to ask him to leave my classroom. My mom (a thirty year teacher) has told me his behavior is inappropriate, and suggested that I say “[His name], I’m in the middle of a lecture, and I need you to leave.” Given that we have collaborated in the past, I’m expecting push back from new boundaries. Oh, and I think some valuable context is that he’s increasingly been more inappropriate with me on after hours phone calls, which I have started ignoring with increasing frequency. The other week, he said, “If we didn’t work together, I think we’d make a good couple.” (I genuinely felt so gross when he said this). I also recently started wearing my engagement ring to work; and he made comments about me being single. I am not. Please help me figure out how to handle this turd. It is starting to chip away at my love for the job to have to interact with him, to the point that I am currently considering quitting this job that I love. Edit: pls help 🥺 submitted by /u/shrodingerschat [link] [comments]