I like someone who has a girlfriend, he nearly cheated on her?

I think he likes me too b/c he was prepared to cheat on her with me but changed his mind at the last minute and said he wasn't a cheater. We spoke for a while as friends then stopped contact for a few months then started speaking again. We met up a couple of times as friends and nothing happened but I told him I like him and he asked to meet me more but then he got cold feet and said he couldn't cheat b/c his gf loves him but he's not sure if he loves her. I've not spoke to him since but I can't get him off my mind. What should I do? If he doesn't know he loves her now then he never will right? They've been together for 2 years. Should I wait until they split before I speak to him again? I dk when they will split but I realli like him