18 year old daughter dating a 17 year old mexican?

My 18 yr old senior daughter is dating a 17 yr old Mexican(a junior). We had liked him until we noticed since Thanksgiving, he gets jealous & accuses her of cheating on him.(They are having also.) He always apologizes, says he loves her & things are GREAT!! His mom said he is depressed due to younger sister illness. His 2 older sisters told BF a lie and had argument on the phone with my daughter. I talked to sisters at BB game & asked them to apologize. One said yes,the other got smart with me. The one did apologize but very rudely. My daughter cried & we left BB game & came home. 1 hr later, cop called & asked me about it since their mom called cop. I told her my daughter is very sensitive & was picked on for 8 years at this school before we transfered her to another school & she doesnt stick up for herself & what BF was doing. Cop suggessted they break up. BF called & apologized & they are back together. My husband is FURIOUS & we are fighting terribly. HELP!!!!