Friend struggling with sexuality

[Dumbledorker101]

My male friend is struggling so much with his sexuality to the point of having suicidal thoughts and depression. He's just begun councilling and so he is discussing it in sessions but also other things too regarding losing his grandparent, grief etc.

So both him and his female partner have been together for around 3 years and I've been really good friends with both of them for a while now. They are both equally my best friends and mean the world to me.
He has struggled speaking to his partner about all this for a while in fear of her leaving him and so h3s spoken to me in confidence about it and I've tried help him and advise where I can. I have told him I am posting on here for advice and he's ok with that.
He's having feelings of overwhelming guilt for feeling this way while still in love with his girlfriend. But he can't stop thinking about men. His upbringing has been quite homophobic in his household too which hasn't helped.

What can he do next? He's having all these thoughts and feelings and yet doesnt want to lose his girlfriend who he loves so much. You can see how much he loves her and cries with the thought of not being with her. I want to be able to help him move forward and I don't know how.
Any advice?

I’m sorry to hear your friends going through this. I split with my partner earlier this month and we had been together for just over 5 years. He was bisexual and I was the first woman he’d been with in over 10 years! My situation was slightly different to this one though as I knew he had been with men when we began the relationship. I think being open about being attracted to men is important for him as I think my ex always being honest about his sexuality around me helped him to feel secure within our relationship. When I found out about his previous male partners I was slightly unsure at first (I have only ever had relationships with men) but I loved him for who he is and did not feel that this should stop our relationship. For me as long as I was his exclusive partner it didn’t matter to me too much as of course during those 5 years we were both bound to look at other people (be it male or female) and think that they were attractive (but of course never act on it). I think it would be worth him talking to his girlfriend about his feelings and from then they can decide if they both want to proceed with the relationship. Btw, my relationship didn’t break down due to this- we had a large age gap and I had a period of poor health where I behaved destructively which made it difficult for our relationship to survive. Sorry if this is really long, I just wanted to reassure that these types of relationships can work- the key is just to be really honest and keep each other in the loop about how they are feeling! Feel free to ask me if you have any more questions

Thankyou for your reply. He told her a few months ago that he is bisexual and it was a huge relief to him. She was a little upset and then since then she's been really understanding about it. I don't know if they have spoken about it since really. I don't know if he would be able to tell her this much of how he feels though and that's the 2orry he has and what he is fighting. To sit down and explain to her that he is having such thoughts about other men he fears will destroy them both. He does love her and so he thinks he's bisexual but then wonders if he is gay but still possible to love her but is it still natural to just love another person so much because of who they are. I hate that he's at war with himself so much over this I can see how much it's tearing away at him