Why would he do that....

The GUY I’m supposed to marry in 2019 has been saving pictures of another woman in his phone and also sending d*** pictures through Snapchat to her. I confronted him & he hasn’t said anything to me about it. I can’t leave yet because i don’t have enough money too & i can’t go to my parents because i don’t like my family in my business. I’m looking for roommates now but I feel like I’m stuck. What do I do? Any advice? I feel like I got boring to him?

* if there are guys on here please respond and let me know why would he do that?