Relationship problems

I’ve been with my boyfriend a little over a year. We’re a long distance relationship. I caught him texting other women and lying about his whereabouts in the past. We moved passed it, but lately it’s felt that something has been going on. I’ve questioned him about it but he claims there’s nothing. I’ve also noticed that I feel that I am starting to loose interest in the relationship. I need advice as to what I should do. Should I leave or try to work on it with him?