Should I trust my husband? How do I get the truth?

So my husband likes to lie ALOT but besides that I recently got laid off from my job and we decided that I would stay home with our 2 kids and he would go get a job but just yesterday he had told me that he was going to turn in some applications and would be right back to help me with the kids but only he didn't. I called the phone of his friend who he was with and he told me he would be back soon and well he returned last night at 2am drunk and smiling like he didn't care at all that he had lied all day and was drunk but promised he wouldn't. I yelled he yelled, he slept on the couch and today I am going on with my day takling care of my kids and noticed a what looks to be a hickey on his neck and when asked about it he replied that he had gotten it from his GUY friend who I also know, and can promise they are not gay! What do I do?