Dear Eric: My former best friend and longtime housemate is a serial monogamist and cannot go a couple weeks without being in a long-term relationship, usually having no more than two to three weeks in between very serious relationships. This friend disappears fully into relationships with people who aren’t good to him, and it’s impossible to get him to respond to invitations to hang out. After months of initiating plans, and rarely hearing back, I decided to take a step back from it due to incredible initiation fatigue. He will occasionally call me and say he misses me and wants to grab lunch.