I think this is either a result of older age or fucking the same women for over a decade. This usually happens with my wife. Particularly, if we fuck more often than our normal. If I'm not extremely horny before fucking ill sometimes get bored after 10mins. Although my erection remains strong, I'll start thinking about other positions or something else to make the sex more entertaining. This happened a week ago. We were on vacay without the kids so we fucked no holds barred On the second night, after about 10mins im thinking..”um should i do anal? nah to much work. Maybe 69? nah. Maybe more doggie and cim? yeah thats it” Its like I sort of exhausted all my sex stimuli with her the night before. lol