Im so 😕 confused 😢

My bf and i have been together since 2010 hes helped raise my now 9 yr old we have a 3yr old and a 2 month old. I just found out he had a sc for months now which is a problem b/c we agreed to not have one. I also found multiple msg on ig from him to several girls. Nothing deep or personal just sexual perverted shit. It makes me so angry and embarrassed to have to admit what i found then when i realize that this is my reality it breaks my heart. Im a #Cancer and loyalty is a huge thing for me. I am the most loyal respectful and devoted partner he could and/or has ever had. Idk why or what or anything right now im so confused!