min styvsyster fångar mig onanerar, hon säger till mig att om jag låter henne knulla mig kommer hon inte att berätta för min man

My stepsister is in the house where I live with my husband, suddenly she discovers me masturbating because my husband doesn't please me, she tells me what she is going to tell my husband, I ask her to please not do it, then she tells me that I won't tell her if I let her fuck me too (Spanish)