["My partner is away getting treatment and therapy and it's hard.", "I'm sorry to hear that.  What do they get treatment for?", 'Oh he just has a lot of trauma from childhood and he takes a lot out on me so he has to get help in order for anything to continue between us.']
I'm sure that's really tough.  I hope he appreciates all that you're doing for him, and I'm sure it'll work out :)
I am very lonely with my man away at treatment but it's necessary.