The fact is for most ppl sex matters. He can still love him/her and want to stay together. But if he is gay, not bi, but gay the craving for men and lack of desire for women will remain. It is what it is as unromantic as that is. If he is bi but has not realized it (some ppl can go yrs before truly knowing) perhaps she will have a chance. If not its a matter of time before a man "steals" him from her. If he can stay with her while gay (not bi) he has an iron will.
The fact is for most ppl sex matters. He can still love him/her and want to stay together. But if he is gay, not bi, but gay the craving for men and lack of desire for women will remain. It is what it is as unromantic as that is. If he is bi but has not realized it (some ppl can go yrs before truly knowing) perhaps she will have a chance. If not its a matter of time before a man "steals" him from her. If he can stay with her while gay (not bi) he has an iron will.