Based on the classical earthly-branch relations of your two zodiac animals — this combination may emphasize these tendencies; real people add the nuance.
Harm pairing — slow drains to watch for
Monkey and Pig form a harm (Hai) relation: neither open war nor open affection, but a quiet leak of goodwill. In practice this shows up as small resentments that are never voiced — the unreturned favor, the misread message. Harm pairs work when both sides over-communicate on purpose.
Say the small things out loud, keep money and expectations explicit, and the leak can be sealed.