I moved out of my boyfriend and my house and we had a financial agrmt that he would pay 1/2 - but didn't help!

at the start, we had a financial agreement that we would pay 1/2 of everything but he ended up not paying any of the rent - I paid each month - and I would end up paying the utilities before they got shut off!!! Now I want to try and recoup my $$. Can I sue or even put him through Court nightmare? Please advise. The total tally in rent alone is 1/2 of 5000! We do not have it in writing and the lease is in his name but the landlord is my friend who knew of the arrangment.