What should I do

I found out 3 days ago my boyfriend / kids dad cheated on me 6 months in our relationship with a school mate in a car they had a quickie while I was basic training in November 2017 we stayed dating in May 2017 . It’s now March 2020 when I got out of basic Christmas 2017 I was sick and found out I had trich and never knew it was from him he lied for years and old Instagram messages led me to the truth . We now have an 11 month old and a disabled premie 2 week old should I stay or leave he wants to work it out . We were having relationship problems at the time of my basic training. I want to just end it bc I feel like I will never get over it bc it took so pong for the truth to come out and I feel like things have been based on lies him on the other hand claims he was scared to tell bc he didn’t think I was gonna rerun home if he confessed and wants to stay a family . What is the best option. I do love him dearly though. I kept talking to my ex at the time and messing with his feelings so I feel it’s my fault he did it I’m just mad it took this long to find out.