while hubby is at work

I have had sex with another woman while my husband is at work. It started a month ago. I had a friend over. We had been talking for a couple weeks about me being bi-curious and horny all the time. We decided to just go for it and see if I liked it and I did. Now my husband wants to know why I bought a double ended dildo. I told him just so I can masturbate with it. I didn't tell him it was so Sarah and I could fuck using it. He would be ok with it if I told him and would probably want to join, but I don't want him to join. I really enjoy the lesbian sex just with her.