oblivious

Often when my mum calls, the same housemate answers the phone (we're the only ones who share the landline). She believes in telling everybody as much detail as possible about her life, and the lives of others, so she's talked to him a lot and thinks he's very nice (he is very nice). I always feel guilty because he's far more solicitous and interested in what she says than I appear to be. He's the housemate I do stuff with the most, too, so he would often come up when I was telling her about things I'd done. For a while, she was asking after him every time I spoke to her, always with the same hopeful tone of voice she'd use to ask if I'd "met anyone nice". Finally, she flat out asked if we were dating (I've forgotten which of her quaint euphemisms she used) and I had to disappoint her and say we were just friends.
Recently she's started using the same hopeful tone of voice again as she tells me how nice he is, every time we talk. Last time she also asked if he would like to visit C'land with me, and said he'd be welcome to stay any time. I don't know if she thinks I'm lying about us just being friends or if I'm reading too much into what she says*. I know she doesn't think I'd tell her if I were seeing anybody (which is probably true, and is something I feel a bit guilty about).
I never thought he had any interest in being anything other than friends (or rather, I assumed, as I usually do, that I was misunderstanding anything that could potentially be interpreted that way), but recently he admitted that he had had a crush on me at some point (from the context it was clear it was in the past and/or he wasn't attempting to do anything about it). He said this when we were waiting for a train, just before one arrived, so the subject got dropped, which I guess is good because I didn't know what to say. I haven't spoken to him much since then, because he's been away a fair bit, but I don't think things have gotten awkward. I feel kind of bad, though.
Should I try to be less oblivious? This isn't the first time I've realised in hindsight that what I thought was the extremely unlikely interpretation, that someone liked me, turned out to be correct, so perhaps I could predict these things better than I usually do. I'm not sure what I could do differently, though, other than feel more anxious and be more awkward, so I think I'm happier being oblivious.



*Actually, perhaps she is just less oblivious than me and has just been trying to give me a clue?