“What would you do if the guy that claims he loves you likes a specific girl’s photos and posts on Facebook all the time. Yet, when you confront him, he just says how it’s a friend but yet he compliments her and doesn’t really write much on my Facebook page.”
Here's the brutal truth, and this applies to both genders:
If your partner frequently comments, likes, and compliments the photos of another person who doesn't contribute to their life in any meaningful way, especially while at the same time doesn't do nearly the same for you, it's almost certain your partner would have sex with that person given the opportunity (if they haven't already).
"Damn girl, another sexy photo."
"I love this one. Probably more than the other 183 I liked."
"Ohhhh baby, Let me know if you ever need someone to cool you down cause you are SMOKING!"
There's a huge difference between simply liking and occasionally complimenting the photos of random women or men (of course, some people may still not like that) and constantly liking and complimenting the photos of a particular person who is not a family member or longtime friend (a friend who they never did the nasties with), ESPECIALLY if your partner won't do the same for you.
Bottom line: If he's been doing this for a good while now, sadly you just don't do it for him anymore, meaning he's lost interest in you and the relationship. You can try talking to him but it's almost certain he will either eventually keep you around but cheat on you or just leave you once someone "better" comes along.
If I were you, I would leave. He no longer respects you and the chances of him changing are ultra slim.