5 year affair - now we are madly in love!

I have been dating a married man for 5 years. He's considerably older than me (28 years), but I feel age is no barrier. He has strayed as him and his wife only have a business relationship, and constantly argue. She even has been known to throw punches. He can't divorce her as he's afraid of taking his hard earned fortune. He lives only 3 days a week with her and the rest he spends in the country just to get away from her.

We see each other once a fortnight, behind everyone's back (I live an hour away). They all think we are just friends. We call everyday and text every night. 2 years ago, he confessed he's in love with me, as I am with him. With each time I see him, we are falling for each other even more. On many occasions we have merely met just to have dinner, then part ways. There's a lot more than just sex.

I so badly want this relationship to be official. For us to show our love to the world and not hide anymore and lie to people. But because of our age, it will be socially unacceptable. How should I tell him? Or should I even be doing it at all? This man has got under my skin!

Thanks for your help.