The movie starts with Deanna Miles (Melissa McCarthy) going with her husband Dan (Matt Walsh) to drop off their daughter Maddie (Molly Gordon) to her senior year at Decatur University in Atlanta. After saying bye to Maddie, Deanna tells Dan how she's looking forward to their trip to Italy until Dan flat-out tells her he wants a divorce because he has fallen in love with another woman. To make things worse, he is selling their house since everything is under his name, meaning Deanna has to leave. Deanna angrily kicks his car and takes an Uber home.

Based on this passage, who plays the husband in life of the party? Let's give stream of consciousness first:
To answer this question, we should know that: The movie starts with Deanna Miles (Melissa McCarthy) going with her husband Dan (Matt Walsh) to drop off their daughter Maddie (Molly Gordon) to her senior year at Decatur University in Atlanta.
So, the final answer is Matt Walsh.