I need advice

As of rn i am 6 months pregnant (almost 26 weeks) due july 10th . Me and my boyfriend of almost 3 years went on a 2 week breakup last august . I had no intention of getting back w him and to make myself feel better i had unprotected sex with somebody else on august 21 . Well a couple days later i got back with my ex and swore to him that i didnt hook up with anyone . I was afraid of losing him again. And then in october i found out i was pregnant . I know that my baby is my boyfriends and not that other guys because i had my period two times within 2 months after having sex with the other guy and i would be a lot farther along in pregnancy if it was the other guys . I want to tell my boyfriend tonight to come clean about me hooking up with him during our break but i dont want him to think that the baby isnt his because hes so inlove with our daughter already . He was seeing 2 different girls during our break and even after until i found out but he swears he didnt have sex with them . We are trying to have no secrets since something about my past just arose to the surface . I swore to my boyfriend we wouldnt have any more secrets but this has been eating me up.