To answer your question on the script. Yes, there is a script. You can find it rehearsed on sites where men swap tips on deceiving partners. There are sites that will show up in his History as 'Sports Talk' or other innocuous-sounding names.
'This is not what it looks like'.
'I was just curious'.
'It was just once'.
'It doesn't mean anything'.
'I think I may be bi'.
'We are just friends/colleagues..'.
'It was a work trip'.
But that is upon discovery of an affair, discovery of an active and promiscuous sex life with other men, interest in gay porn, or confrontation about the horrible relationship (if you are very persistent and force some sort of admission). Before then there are constant subtle and not so subtle messages to you that you are not enough, that there is something not altogether attractive about you.
'You are crazy'.
'You are oversexed'.
'I have an early meeting'.
'Again?'
There are many ex partners of gay men who suspect that the term bisexual refers to a man who just hasn't yet found Mr Right. Or alternatively, that so-called bisexual men are just one woman shy of being gay.
It is the comprehensiveness of the lie you may have been told that means you absolutely need to know the truth.
[[http://a_musing.blogspot.com/2007/10/four-former-wives-of-e'Bi Gentleman' that I think is a heap of self serving hooey. Many of the other posts illustrate the EA, the psychological abuse, and the sexual abuse (as in, rejection and no sex). And there are the reminders that the gay partner has a lot of stuff of his own to deal with.
Is integrity too much to ask for in someone?