From my best friend:

I'm 42 years, healthy and decent lady, my partner is 47.
We've been together for 3 years, and we haven't had sex for almost 2 years. Although I exercise and have a nice body, he has no interest in sex whatsoever, and every time I try intimacy he gets very upset.
Last year, I had to spend one month away for work and he came to visit once. When I came back home I found a pack of Viagra empty and bought when I was away. I confronted him and he promised that he never cheated me, and he was trying the Viagra alone to see if he had any reaction, but it only gave him a big headache.

2 months ago, a found out that the cheated on me with a 23 years old girl that works at the same place. It was devastating. He said he had sex with her twice, and that happened when I was away. He beg me pardon, he promised he would never cheat again, he said he would do anything to are things work. He said he didn't work with her either and that he was only setting for the last year, but he never touched her again because he realized it was wrong, that he loves me with all his heart. That he took me for granted, that he'd do anything to make it up for all he the hurt he did to me.
They've been speaking for one year, I just found out because I saw her message popping up on his phone and decided to check. He spoke openly on a very sexual and nasty way. And he kept promising her, that they'll make it again soon. He said that his girlfriend was in town, but that he will arrange something soon.
On the last year, he started being very rude to me, he even called me 'f** bi**' once.

I decided to give him a second chance. But it has been 3 months, and he still doesn't show any interest in sex. I'm feel terrible and lost. I really don't know what to do.

I start suspecting that maybe he is still in touch with her.

Please I need an a advice.

Thanks everyone