Nona I tried your method but my lack of social skills makes this hard to judge so I'll just post the results. >1. Refuse sexual interaction for a while.
I did this and he immediately asked me if something was bothering me, if I was on my period or if he did something wrong. I explained I just wasn't in the mood but he refused to drop the subject and ranted about how it's important to talk things out if the other person did something wrong. I reassured him I wasn't angry and he seemed to calm down for a while but when we went to see a movie he kept saying stuff like "you know you can trust me, right?" and it got me thinking if he's trying to manipulate me. >2. See how he behaves around other men.
I had the opportunity of hearing him and his friends play board games a while ago. Other than him gushing over the female miniatures he paints, he didn't talk about women. One of his friends did say something that pissed me off, something like "I don't care if they're fat or ugly, I fuck as a community service" but the other guys barely acknowledged the comment. >3. See how he treats his mama or other female relatives.
He has an incredibly close relationship with his mom. To the point they seem to trust each other more than anyone in the world, which worries me a bit. He's also very defensive about his two cousins and best friend, who he says he sees as his sisters, and protective/spoiler of his nieces. I think he's clear on this one but I fear he may be a momma's boy.