Is my hubby having affair with my colleague?

My hubby and I work for the same company and have the same friends, including colleagues. We've had a lot of people at work tell us that they admire our relationship.

My colleague is having an affair with a married man in her office, but to get him to leave his wife, she started getting close to my hubby, which started rumours of a possible second affair. (Bare in mind that this colleague was married twice before).

My hubby told me everything about the situation but her boyfriend threatened to tell me, so my hubby arranged a party to get things straight.

The colleague and her boyfriend ended up in one of my kids' rooms the night of the party, which made my husband very angry. This caused a whole argument between us.

I don't trust anybody at the moment, including my hubby, because he started acting very strange towards me (he had an affair before we got married).

I think he's falling for this woman, who spends a lot of time in his office. And I think this woman wants me to see that there's something going on, although I don't have any proof.

What should I do about this situation because all eyes are now on me for a reaction?