Would you leave after discovering online infidelity?

Together 10 years, engaged 1 year. Found receipts for paid web cam interactions when we were supposed to be saving up for our wedding. Not sure what to do now. We have been together since I was 20, so I have never dated as an adult really, and now I'm wondering if I'm going to regret taking this next step with him.

Its the lying I'm having a hard time getting past, as I had to find this all out myself, so he would probably still be continuing the behaviour if I hadn't have found out. It makes me feel like his mother

I want to settle down and have kids and am so so worried that I just spent the past 10 years with someone who can't be loyal. Starting over as I'm approaching 30 feels daunting, but so does staying another 10 years in a relationship with someone who can lie to me like that.

We have a great connection, he shows up for me around the house, like aside from this I thought we had a perfect relationship. What would you do?