Well actually there's an anal scene between her and Anthony their first night in the new house, which is unavoidable. You only get to choose whether Myriam is more exhibitionist and agrees to get in the pool naked, which leads to Anthony fucking her there. If you choose to have Myriam wear a swimsuit, she gets shy and only agrees to do it in the bedroom. In both cases she does it willingly and enjoys it. But in the former case, she gets excited by being nude and has an orgasm. In the latter case, there's a connecting scene, with Marc hearing them in the adjoining bedroom, and masturbating to Myriam's cries of pleasure.