Vegetarianism and Buddhism have a complex relationship. Different areas and lineages will approach the problem differently. Also, there are different expectations for monk/nun and lay practitioners. Here is an excerpt from
An Introduction to Buddhist Ethics by Harvey:
It is often seen as surprising that vegetariansism is not more widespread among Buddhists than it is, given the Buddhist teachings. In fact, the Buddha's emphasis was on avoidance of killing. So it is worse to swat a fly--an immediate act of killing-than to eat the carcase of an already dead animal. Only in certain Mahayana texts is vegetarianism advocated.
Typically,in most Buddhist countries monks are expected to eat whatever they are given on their alms rounds. So if they are given meat they eat it. They certainly would not kill the animal themselves and they should discourage someone else from killing an animal for them. The rules for lay people are even more relaxed.
I think regardless of whether one eats meat or not, the true spirit of Buddhism is to be appreciative of the lives that are sacrificed to make our meals possible. I think that sometimes that reverence will naturally lead to the desire to minimize life-taking and therefore becoming a vegetarian might be the next most logical step.
So your partner can eat his sausage, but only after he thanks the pig!