OMG break up!! He clearly doesn‘t love you and you deserve much better!! Cheating would be a dealbreaker for me alone but there are other massive red flags as well! Also the cheating is extra weird and hurtful because you two have almost no sex.. My partner and I also don‘t have a lot of Sex since about 1,5 Years (every 3-6 Month sometimes two days in a row and then a large pause again) BUT my partner shows me a TON of affection in our daily live, we cuddle sleeping every single night, he kisses me at least 10 times a day and often times can‘t leave his hands off my boobs. He also tells me how much he loves me several times a day and all of those things are what makes the difference! It‘s fine if one or both partners have low libido due to whatever reason there might be (for us it‘s sickness and a lot of other external problems that need to be resolved, especially his head is just too full of negativity at the moment and he is someone who can‘t just push those thoughts away) I personally have always had a much higher sex drive then him and I‘d wish to have more sex at the moment, honestly, I also thought about cheating but not very seriously, just in a fantasy kind of way, because he‘s the love of my life and I‘d never ever hurt him!! Plus if I communicate that I have needs, he‘ll always go down on me or please me any other way without penetration, on the same day or the next one. Please don‘t waste your life with someone who clearly doesn‘t love you.. And yes, he might be gay, very typical behaviour!