It is hard when a partner comes out after years of hiding their interest in the same sex.
You seem to be wondering, is he bi or is he gay? Does he still want me or is it really men he was wanting all along? Will he want to throw himself into sex with men and ignore my sexual and emotional needs?
You can't know this unless you ask him and get some answers. Hopefully he does love you and still desires you. Extremely honest and respectful conversations are definitely needed here. This is understandably very difficult and unsettling for you!
A queer friendly therapist might be useful. This is a fairly common scenario in our culture, where men often feel compelled to hide their homosexual feelings and take a wife as a "beard." Hopefully your partner is bi and really craves sex/love with both you and any prospective male partners.
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
Mags (poly, F, 61) loving miss pixi (poly, F, 39) since January 2009, living together since 2013
"Master," (mono, 34), miss pixi's Dom for 2 years