Husband cheated on me?

so as some of you know from pervious questions after my husband and i had our third child he changed alot and now enjoys partying and drunking with his friends and other girls then hanging at home. That being said our kids are 6, 3 and 1 month. My huband is 23 and I;m 22. So I texted him because he always gets to leave to come home or go out for lunch. I was like come home we need to talk or me and the kids were walkin so I made him lunch and we talked for half an hour.. I asked him about the girl my friend saw him with and he said that they have kissed and that he is truely sorry because he was wasted ( which i do not think is good enough excuse to kiss another women). Turns out she is also 18 and he was buying her alcohol - hes one of his buddies sisters. He said she meant nothing to her but he needed to feel loved because when he got home i would be with the kids and never wanted to have at night. I WONDER why i just had a baby? we had once after i had my daugther ( 2 weeks later) because he wouldnt stop begging me and he told me i didnt enjoy it. I'M STILL healing. I just feel like he turned into an immature mess like he wants me to put him before our children, which i wont do. I'm having my mom watch the kids tonight so we can go out for dinner and just talk but i'm not really sure how to handel the girl situtation because if i guy even looks at me he gets mad a me because " im dressed to y." but he wants me to forgive him for this? I'm just lost.