Just to let you know large and small can get along.

I have a 160lb Great Dane, male
15lb MinPin, female
74lb Boxer, male
13lb Pom. , female
65lb Boxer, female
45lb Balck Lab, male
More,but you get the point. They all get along fine. The Great Dane and the MinPin have a very close friendship.

Just thought it be a good idea to let you know in can work.
Give it time.
Here's the Dane and MinPin toghter.