Newhere, what a shock for you.  You must be feeling incredibly confused and upset.

Firstly, he may well have had a sexual experience with a man that night.  A lot of us here are familiar with 'trickle truth' where you hear parts of a story or find out something accidentally and then get told part of a story. It can go on fir years like that. I could almost guarantee there is more going on than you have been told.

You know when kids break something, they hide, evade, lie, partially admit then burst into tears hoping to mitigate punishment? Thats what you are looking at here. 

Secondly you are not obliged to fulfil every sexual desire or fetish of your partner.  If you don't like anal play you don't have to participate.  No guilt required. It's ok to say no thanks. His possible homosexuality is not your fault.

Thirdly - only you know what is acceptable to you in a relationship. 

Is it ok that he stays out until 4am carousing 'alone' (yeah right) then comes home drunk and cries on your shoulder?

Are you prepared to live with your doubt and his already demonstrated lack of honesty? He's using porn and toys alone - did you find his anal toy or did he tell you about it? If you accepted that, and now his drunken nights out, and now his weepy confession, what's next?.  He's pushing the boundary seeing what he can get away with - because 'his needs'. Infidelity has either already happened or is the next step.

Are you going to be the marriage police, monitoring his movements, checking his phone, hacking his emails, wondering, wondering, wondering ... how much evidence will you need and what will you do if/when you find it?

Are you going to keep assuming blame and beat yourself up about his choices as if you drove him to it? You didn't. He's a grown-up.

Start thinking about how you want to live and what sort of future you want.

And get tested for STIs as soon as you can.  (Sorry.)

thank you both for your reply. to answer your question - yes, i knew about the vibrators and pornography and it doesn't bother me. I often hear that prostates are sensual areas for men of all kinds, so assumed that's what this was about. We spoke about it more last night and I think he is honestly extrapolating from his interest in anal play that it must mean that he is gay. This is confusing for him because he is attracted to women. I can confirm this as over our many years together it is very easy for me to arouse him, and his sexual appetite is a very very active one. 

I'd like to know, given his expressed heterosexuality for so many years, is it possible that he just has a very high sex drive and is also interested or fantasizes about men because they are a bit taboo and out of reach for him, e.g. very naughty? I have fantasized about women before, but I know I am certainly straight. 

could that be what is happening here?