Can you get pregnant using condoms?

Im 31 weeks, and i feel so bad i dont know what to think or do....I cant wait for my baby to be born already....i have a boyfriend for the last 3.5 years with who i have a baby girl that is 20 months. Im divorced of my husband of 17 years with who i have 4 kids. Me and my boyfriend took some time and he moved out of my house for almost 6 months but we were having sex all the time. But i was seeing my exhusband and having sex with him also but with condoms all the time. Im not seen my exhusband anymore of course since i found out i was pregnant but i cant even sleep well at night thinking if theres is a posibility that this baby could be of my ex. I dont think so but anything can happen 😞idont know wht to do or if i should tell my boyfriend everything that happens or just wait for my baby girl to be born.

Please let me know what you guys think 🤔😩