Hmm he is kinda jerk friend, but it's not like Miura would surely date Ryouhei if he'd reject her. She knew Ryouhei before him and she wasn't interested. He is more of a jerk towards Miura, but he is still a teenager, who only starts to sort out kinds of love. Teenage years are the time for exploration of this sort imo. Also, I'm not really sure if my views are right, but I think that people can to some extent develope bisexual tendencies, so he may end up being closer to his goal as "married, secretly gay". Personally, I wouldn't care if my husband would practice safe homosexual sex if he stayed a good husband and father in other aspects.