Delicious Problem

My boyfriend has a huge cock. It's almost nine inches long and so very thick.
When we first got together, we were fucking like rabbits and I often suffered for it the following day.
As we've been living together now for over a year, the sex between us is still good. But it's no where near as good, as when Frank our neighbour from the downstairs flat, fucks me.
His cock is just over six inches, reasonably thick, but and I genuinely do mean this, I much prefer the fifty two year old fucking me.
With my boyfriend it's hammer and tongue the whole time. And sometimes that's how I like my arsehole being fucked.
Yet when Frank and I fuck, it's a much longer sexual experience where we both suck cock (My boyfriend won't) Frank rims me for an age which I adore (My boyfriend doesn't rim) and we definitely enjoy lots more positions in a more sensual way.
Only yesterday with my boyfriend at work, Frank and I fucked in the missionary position kissing the entire time, but not before we'd spent time in the shower washing each other and Frank devouring my back passage.
After he'd cum in me twice, he asked me a question "Would I ever consider moving in with him".
I said I'd think about it because of my boyfriend. But in my mind I desperately wanted to say yes.
I know there's an age gap, but the time Frank and I spend together, we talk, hug, kiss and fuck like true lovers.
With my boyfriend its nothing like it. Nothing at all.
Now I have to decide if I should move downstairs.