I feel so indifferent. Please help

So I’ve been married for 4 years and we have two kids trying to a third.

My husband told me he would think a MMF three sum would be fun and he’d maybe like to do it. He didn’t pressure me or anything just voiced how it would be fun.

He’s had one in the past a long time ago. But we don’t really discuss our past sex lives.

I’m not sure how I feel about it yet. Like does this mean he’s bored with me? Doesn’t love me?

We are VERY adventurous in the bedroom as we are now. I try anything he wants and he tries anything I want.

But this? I don’t know.

I told him how I don’t think marriage is letting someone else plow your wife.

His explanation is he wants to see me be pleasured and have the best orgasm. That he wants me to be the center of attention and be worshiped sexually.

I asked if he wants this only to ask for a FFM three sum in the future and I would have to let him since in had a MMF one.

He said he doesn’t want sex with any other woman.

He swears up and down he loves me more than anything and that it’s just a thought that he’d like to try.

Also folks, he’s as straight as they come.

I said how it’s a fantasy but sometimes fantasies are just that. A fantasy and not reality.

Advice?

I mean isn’t that what a lot of women want is to be worshipped sexually and most women want two attractive men?

I can’t help but feel anxious and awkward around him.

Please help... what would you do?

I’m worried about the repercussions. The mental health after. The dynamics.

But if I say no. Will he resent me?

I’m having a hard time here.

Any advice? Thank you. And please no insults or anything to make me feel like shit.