How to rebuild trust after cheating

Mr

Anyone stay after they found out their partner is cheating? My husband was cheating on me with his ex wife, as you can see from my profile they have kids together and so obviously she's going to be around... forever.

He wants to fix it and he says it's just sex but he wants me, etc. We're trying to stay together because we have kids, but I don't trust him... at all. Everyday I know he loves her more, but the only reason he's with me is because she left the family.

I dunno, he told me that I can't expect immediate change that he needs time to prove he's faithful, but it sucks. I need advice since I see this lady daily