how should I confront my boyfriend or handle this situation ??

I think he likes another woman and it's bugging me. I don't even know if he'll be honest about it if he did like her but they work together. I'm just not sure how to handle the situation if he does but I'm not sure if it's my mind playing tricks on me because I'm insecure about our relationship or he's really into her. It's pretty tricky to discuss with him because I don't know if it's appropriate to bring up. I just do know I want to figure out how to keep him interested in me. I feel our relationship has gotten very dull and predictable and I just want to know how to put the excitement back into our relationship. It's starting to make me not trust him and I don't want my insecurities to become toxic with the both of us. It's devastating to think he may be interested in someone else but I don't know what to do to spice things up.