My husband lied to me and betrayed my trust with another woman

my husband(36) and i(38) are in a long distance marriage currently. My husband has this female friend that im not exactly comfortable with. I tried striking up a friendship with her in order to feel more comfortable about it. During an argument he decided to go to a bar without telling me about it but i found out through other means. I was texting this female friend and told her he was at a bar and i was worried because he was angry. She offered to go there ( since she lives close to him and i dont) and check on him. i told her no i didnt think it was a good idea then she replied that she was already on her way. she then texted me a picture a little bit later of him at the bar by himself then she said she got a table in the back to get something to eat for herself. she texted back and forth with me the whole time saying he hadnt seen her and he was alone. A few days after this my husband decided to come clean about it. Apparently they were together at the bar the whole time ( before she even offered to check on him) and in fact created the scene for her to take the pic and he was the one texting me from her phone some of the time. they decided to keep this all from me. I feel betrayed, they lied to me and played me for a fool. i feel like i cant trust him not to keep secrets from me and especially with her, he said she was his friend and he would continue to keep thier secrets together. i also feel like he is willing to lie to me about her. he was also concerned that she not know that he told me because he didnt want to upset her or lose her trust. i dont want to throw the marriage away but i dont know what to do. I need advice about what to do