How to get over the guilt?

I’m a 55M who is new to the poly world. I met a married mom on Feeld who has been ENM for 3 years but only had 1 steady boyfriend outside her marriage who she broke up with earlier this year. We’ve been dating for about 3 months now. I’m her only partner besides her husband who isn’t satisfying her at home. It feels in many ways like we’re having an affair rather than being in something poly.

Coincidentally, we both had someone reach out for a first date last week. That sparked a slight reaction of jealousy in both of us but we agreed to go on the dates (coffee/ walk and dinner, nothing physical). Afterwards, we both thought it best to just focus on us and decided to just see each other for the time being.

So how do I go about potentially adding another? I’m hesitant as somewhere in me I’m somehow registering it as cheating and have a sense of guilt.