Lying ex

So when I got pregnant I already planned to be a single mother cause my ex could not control himself when he is drunk and gets violent. My baby is now 4 months old tomorrow and the past 2 weeks me and my ex have been trying to fix things. He has started a new relationship and she ended up pregnant but I was told they had broken up and he doesn’t believe the baby is his cause of her ex. Well in the 2 weeks that we have been trying to figure things out he has been sleep at my place so he can see what’s it’s like over night with the baby and the morning. Well today I got a message from his supposed ex and she says they never broke up and he lied and said he has only been over for New Year’s Day and that was it. During our time together we have had sex unprotected and I may be pregnant again. I told him to stay gone since he lied and even though it is about my son I can’t stand the look at him and I don’t want him in my house or him to ever lie to my son. He is suppose to be spending the next few days with my son before he leaves to go work in the south but he lied to get out of seeing him and now I don’t feel like he should get another chance.