I can relate to this as DH works long hours and only sees DD at breakfast time, Mon-Fri.
On weekends we seem to spend a lot of time apart, me doing housework while he plays with DD, and him doing gardening while I play with DD. It's crappy but we can't afford a cleaner.
I make a point of getting out every day, meeting up with mums I've met, going swimming or to rhyme time or play groups. One day a week I prefer not to plan anything, so I can mooch around at home and catch up on jobs.
It can be boring and soul destroying. I sometimes wish I worked part time (but am still bf 9 month old so that would be tricky) not only to have some time "off" (ha ha) but also to have some money of my own.
I go for a walk, sometimes two, every single day, no matter how foul the weather is. I'd go crazy if I didn't.
I've found having a baby is a great ice breaker, and I've made friends with mums of babies a similar age at swimming, baby cafe, GPs waiting room... It's hard to make the first move but in my experience other mums are glad if you break the ice. For the first time, after 5 years in this town, I feel I know people and I nearly always run into people I know in the street. It's a pity we have to move away and start from scratch. But I feel braver than I used to about making friends.
Once you've met one or two people, going to each other's houses can be great. The kids can play with each other, and the mums can have some adult time. Even though DD is only 9 months old, I can see this is already a good thing, plus she enjoys seeing other toys!