Why do MEN cheat and lie????

I have been married for about 4 yrs now but altogether 11 yrs. My husband has cheated and lied, well he still lies. But do they ever stop? We have talked about it like we should and I thought we were passed all of that, but I keep finding messages with other women. It just pisses me off that i have forgiven him so many times so we can keep our family together we have 4 kids, but he doesn't seem to care because he keeps doing it. I'm angry with myself because I hate that it feels normal to me now. I just want my family together, why won't he stop?