My boyfriend seems increasingly interested in other girls lately. He tells me often about other girls hitting on him at work and he recently asked me if I want to have a threesome with a girl he invited out to a show (he's a DJ and invited her to perform as a hoopist). We've been together for two years and moved in together a few months ago. He's very loving and wonderful, tells me I'm beautiful almost daily - he's a real dreamboat. I would marry him and I haven't felt that way before!
Unfortunately however, I've noticed we're having sex less and less often. It seems to trade back and forth who's libido is waning (sometimes he rejects my interest, sometimes it's the other way around) but I'd have to say that he has been initiating sex less (though he still verbally expresses appreciation for my "sexy body")... I'm feeling increasingly suspicious and jealous where I never used to - I even read a text sent to him by another girl (same girl he wanted to have a threesome with) where he asked if she needed "a couch to crash on" before he'd asked me if it was ok... I know I shouldn't have done that and it's not my style (he handed me his phone to call mine when it was missing and I just got curious)... it's just that knowing that he was trying to set something up bothers me.
Why do I feel so insecure? He never gets jealous of me (that I can tell). I know he loves me, it's just hard to see him losing interest in me sexually. To be honest our sex life has become a bit boring (and I think that we're equally at fault for that). I know it's common for men at this stage. He seems to be less interested in spending time with me in general... when I come home from work he's just usually playing his video game and doesn't even look up. What should I do? I fear I'm becoming his little house-mate/wife instead of his lover.