boyfriend is getting on my way

Well, you should know better than to ask a bunch of (mostly) men whether you should listen to your boyfriend. :-)

It sounds to me like your boyfriend wants to play audiophile while spending your money. That's probably not worth divorcing him over, although he may become more of a nag if you resist. In that case, all bets are off.

As for the amps, The Bryston's a great piece, and I don't see a word in your post suggesting that you are at all dissatisfied with it. Nor do you sound like the kind of person who enjoys changing your system around just for experiment's sake (or the fun of it). So don't.

(If you really want to drive him crazy, tell him you've decided to become an objectivist, and you now believe all amps sounds the same.)

Don't even consider switching amps unless you can A-B them in your system in your home. I doubt very much the DNA-2 will make much, if any difference, and it may not be a difference you enjoy. Tell you boyfriend to buy a DNA-2 and put it in his own system if he likes that make and model so much.

"trust your own ears"..... Sdcampbell said it perfectly.
It's your system, your money, your ears and your choice.
You MUST always audition the piece of gear in your system before you buy it. This is the only way to buy.After all isn't it YOUR system.
If he wants you to have a different amp in your system have him buy it for you.
Just my $.02, Rick

Go all the way - PS Audio HCA-2

Let's see if I'm clear about this... your choice is to replace your Bryston 4BST or your boyfriend or both? Yikes!