There is modern English slang that is in-fucking-credible.
Further you could say various forms of reduplication are discontinuous, such as the Greek perfect, where reduplication and perfective suffix must come together or not at all, similar to Dutch/German ge-werk-t. Present stem lu-, perfect stem le-lu-k-, where le...k- together mark the perfect stem. A few verbs also have reduplication in non-perfective stems, but then many Dutch/German words also have ge- in non-past-participles, like ge-voel. To both ge...t and le...k- applies that they are perhaps best considered two morphemes each.
Seperable verbs might also count as discontinuous, but they are certainly not single morphemes.
There is a Dutch h + reduplicated vowel that are sometimes informally used as an infix for emphasis, mainly in speech:
KPN dwingen om de post op zondag te bezorgen? Dat kan toch niet, wat zei ik nou net: KPN is een ondernéhéming, geen staatsbedrijf.
"Force KPN (postal service) to deliver the post on Sundays? You know that isn't possible, what have I just told you? KPN is an enterpríhíse, not a government agency." However, I'm not sure whether this hV should be considered a morpheme rather than just a phonetic bit of...something.
stem
-t, but il ne me l'a pas donné.