Twiglet my ex did the same when I had DD. He barely visited while we were in the hospital which is literally 200 yards from his office, and when he did visit he was bored, distracted, didn't want to be there and it just depressed me and made me feel like shit. He then only took a few days instead of the offered 2 weeks and spent those days off out doing his own thing. In the nights he did not help once, he was snoring his head off whilst mum and I were both up trying to work out what the hell to do with a screaming DD for 3 hours. He let mum do everything, all the cooking etc and just sat back being served his dinner and beer. I am actually really looking forward to doing those early days again without him ruining it and making it 1000 times harder and upsetting this time!
Tisgy DD was 4 months, we had a joint 30th birthday party for her father and christening so everyone only had to travel once. It was early enough that she was still tiny and everyone got to meet her as a baby, but late enough that I was back down to a decent dress size, all healed up and sleeping better and in a routine, DD wasn't so demanding and delicate and was OK with the crowds and big day and it worked well. As usual her father was off doing his own thing and getting shit faced but then it was his birthday so understandable on that occasion. 
Posy don't feel bad, pregnancy is knackering, we do need extra rest and we do have less energy, those who love us will understand that, especially if you usually would help and do your share. I'm sure your DP just appreciates the human you are making!! 
Venus usually my mum and I would kill each other after more than a couple of days together, but when I had DD I was so grateful for her being there. She flew into the house, cleaned it top to bottom, went to the supermarket and stocked up the cupboards, made sure I got 3 meals a day, kept it clean for visitors, helped with the nights, made sure the laundry was done, took DD out when I needed a nap or shower or just a break, she was an absolute godsend. Usually I would have hated her doing any of that, taking over, fussing, messing with my house etc, but for that few weeks it was exactly what I needed. This time I've already booked Dad to stay before the birth to help me when I'm really immobile, and mum to come down for the birth and do what she did last time. Both of them are banned from the actual birth, I'll be doing that alone, but they'll collect DD and be on the ward waiting for when I get back to the ward with the baby. 