Friend parking there car on my property with out permission

Just wondering if I am insane? My partner and I just moved and his friend immediately asked if he could park his car for 3+ months plus while he’s abroad. I said no - my partner declined my wishes and his friend dropped off there car today. I also have 5 kids work full time and have more than enough on my plate. My partner has also been out of work for many months out of this year and I am taking the financial burden of his. Am I an asshole if I get this car towed? I have put myself into financial crisis supporting him because of addiction.