But that’s coming from the OP, wanting a ‘forever thing’ type of relationship.
Nothing she has said is suggesting that he doesn’t want a forever thing with anyone and is just waiting to be with his late wife again when he dies!
Nothing suggests that he isn’t ready and wanting to be with someone else - and he’s been dating OP for 6 years, and she says he loves her!
I think this has nothing to do with him being a widower, from his point of view. Yes, he hasn’t suggested living together - but neither has the OP! Maybe he’s happy in his own space, maybe he’s shy to ask, maybe he’s just not that committed - none of that is about him being a widower.
I met my widower on line - he told me he got really fed up with people making assumptions about him because he was! He declined a second date with one woman who then sent him links for bereavement counsellors - he’d just thought she was a bit dull!
The “issue” of the late wife, is all coming from the OP. He boyfriend rarely even mentions his late wife.
I think OP should deal with her own jealousy issues first, and then if she thinks she can get over that, she should ask him what his view is on living together.