Is this a red flag?

My husband (42m) was found by me (38f) in the quora forum polyamory several times. I'm not into that type of thing. We are on the verge of a divorce. Is that why he is looking at this lifestyle? He doesn't want me to divorce him. Maybe he wants to have me stay so he can eat his cake and eat it too,but Im not going to say yes to this bs. He's never brought it up, but there's no way he would ever think I'd be into that sort of thing. Maybe he's just cheating on me with multiple people? That has been. A suspicion of mine and he has done it in the past. Is this behavior of infidelity? I'm just so done right now. We have 3 kids together. This isn't cool.