Is my man bi or bi curious ?

Stephanie • Peace ?
Me and my love are very active sexually. We love learning about eachothers likes and what makes us tick ... Im an open minded girl who happens to be bisexual and i like to try new things... (With him only)Althought i question if my man is aswell(bi). A couple times During sex , hed tell me little things like him wanting his nipple licked and wen ever we bring up him in any gay form he plays around and turns it into a joke. Is that a sign of being gay. Or am i just to dawm curious. Is it possible he may like men too. If so, How do i get him to open up if he is..id like to know...not only for the lookout but if he is, id want him to feel comfortable about it with me.i dont judge him. I love him ..and his likes:) I dont mind. Please give me some advise .