Another falling for FWB question?

I'll try to make this short. I was at a house party and met a guy who was a mutual friend of the person holding the party. We instantly clicked. We talked literally for 5 or 6 hours. By the end of the night we were both too drunk to drive. Long story short, we ended up in bed together. He is married, which he never tried to hide, and his wife was in an accident that left her in pretty bad shape. She can barely communicate (confirmed by the mutual friend). He kept telling me how great it was just to have a conversation with someone. About a week later we talked about becoming FWB (friends with benefits), which has been going on for about 6 months. I have been in a relationship for about 12 years (not married because I can't bring myself to do it because I am not in love. we're pretty much roommates, we don't even sleep together anymore.) I have a 5 year old child. Anyway, Our last meeting was amazing and within the last couple of weeks we have started calling and texting each other a lot more. I'm really starting to fall for him. He's made it clear that he will never leave his wife and that he loves her very much. He is scared about life after she pes away. I have never wanted him to leave her or pressured him in any way. I really respect what he is doing for her. My problem is that I can't stop thinking about him. Both of us agree that we have never clicked with anyone socially or ually the way that we have clicked with each other, and I enjoy being his 'outlet'. I enjoy the conversation and the . How do I end the FWB arrangement before I fall head over heels in love? Should I just tell him how I'm starting to feel and let him decide if he wants to end it?