Ok, first of all I am very glad that you are paying attention to your gut instincts. A lot of people ignore these types of signs, which is very unhealthy.
-He Could Very Well Be Cheating.
First of all, we need to get out of the way that there is a possibility your boyfriend is cheating on you. Showing a lack of interest in your sex life is a symptom that he could be getting his needs met elsewhere. Also, the later out pour of affection towards you could be a way to relieve his mounting guilt. To relieve your suspicions of him cheating you need to start looking through his phone records, computer, and bank statements. There are also many affordable ways to use technology in order to catch a cheating partner. Always looks at reputable sites, and always do your research before purchasing anything, or using someone’s services. I know you might think this sounds crazy, but I can promise you that in six months from now if you’re still feeling this way; you will know what, “crazy,” really is. Even if he isn’t cheating, the fact that he doesn’t care about his lack of sexual advances toward you; and how that makes you feel isn’t right.
-This Might Be a Physical Issue.
Men can easily have physical problems pertaining to sexual dysfunction as woman. No matter what age your boyfriend is he could have an imbalance or lower level of testosterone in his body. A lack of testosterone in males can cause mood swings, erratic behavior and depression. A simple blood test can rule this out immediately. I would suggest to him that the whole family needs to get a checkup. Make an appointment and ask him to test his testosterone levels. If he thinks that is an odd request, just say you read something about how it could save your life and rule out many types of disease; which is true anyway.
-You’re Not Drifting Away.