As one gets older it is harder to make friendships – in general.
My personal experience is to keep good friendships with close relatives ( siblings, cousins ) and with my wife’s siblings and close friends. I find that my wife is a more sociable person and organizes our social contacts. Having young children adds an extra dimension – you get invited to birthday parties and it affords an opportunity to meet people.
However It does get lonelier as one ages. People change with age and hence relationships will change too. A friend of mine told me that I was one of the few people he knew who had not changed much in our fifteen year friendship.