I Want To Be Shared Once In A While

My husband is fairly open minded, but I haven't been able to tell him yet about an obsession I developed. A few months ago, he had me use a dildo while I was sucking his dick. He told me to make myself cum while he was in my mouth. All of a sudden, I was fantasizing about two men having sex with me and I had a tremendous orgasm. When I had the orgasm, he came in my mouth. As we lay in bed, I kept thinking about being in a threesome with my husband and another man. I think about a different penis in me. Knowing my husband is watching. And I imagine he is masturbating as I am being fucked. It's a pretty intense fantasy. Problem is, I don't know how my husband would respond if I ask him to share me. Just once every now and again would be enough. I love my husband and do not want to do anything that would jeopardize our relationship. But, I keep thinking,, given that he asked me to make myself cum with a dildo while he was fucking my mouth, he doesn't know how to ask me to share myself. On a couple more occasions he has had me use the dildo while he is in my mouth.