Sex after birth??

Me and my partner stopped having sex when I was about 30 weeks pregnant because I was scared of miscarriage ( I've had 3 already). I got induced at 36+1 almost 4 weeks ago and had a baby girl. Anyway because we haven't had sex for a good while we were both really horny last night and got touching each other then we had sex. We didn't use protection because we didn't have any, he pulled out but now I'm worried about infection, I saw a post on here saying you should wait 6 weeks before having sex? (only saw the post 10min ago)