I'm bi-female with straight boyfriend
It's kinda hard for me to work it out specially when there were times I feel that my partner does not give that same need I feel when I'm with a woman. But still I manage to keep that loyalty in the relationship because I respect and love him and no amount of lustful need of me will ever destroy that. I've thought but never attempted, I talked but never done it.
When you trust yourself to be faithful and loyal then there's no reason to be scared that your partner will leave. If he'll leave then it is never your fault that you aren't enough regardless of sexual preference.
Staying and leaving is a matter of choice but
Love is not.