My wife recently had a baby and we've started having sex again. But it feels different inside her? Is this normal?

Yes, it probably will feel different for a while. Make sure she’s doing plenty of pelvic floor exercises to get her muscles nice and taut again so that it feels like it used to. These are the muscles you use when you stop urine flowing. The way to do the exercises is to squeeze and relax, squeeze and relax, over and over again. It’s important to ensure that her abdominal muscles are relaxed as she does this so only the pelvic floor muscles are being used. Three key exercises are: squeeze and relax slowly and rhythmically; squeeze and hold for three seconds then relax; squeeze, squeeze a bit more, squeeze a bit more, and a bit more, then relax; and for more advanced work she imagines she’s got a pen in her vagina and writes “I am one hell of a sexy mama!”.