So I'm in my second serious relationship, my first however with another girl. We've been together since November of last year and she has a little one [k7] from here previous marriage. So here's my struggle, her ex has never been in the picture due to a drug history until recently he wants to step back into the picture for his child and I coming from a very similar background think that's awesome but I keep thinking my girlfriend would be better off with him. She tells me there is no way they'd get back together as he was awful to her, but even though she reassures me I still dwell on it.

The ex is doing a lot better in life and is trying his best for there kid and I think he could provide a better life for them currently as im in school working a part time job.

Also our sex life has been at least in my opinion getting dull as she just lays there and doesn't really seem all that interested in it ever and I always tend start the sexy time process. I'm a extremely sexual person and like to talk about and try new things and she doesn't really ever, even when I ask her some of her favorite kinks, ect. But I don't like pressing the subject because she says in her past relationships that has always been a issue and makes her self conscious.

I really love this girl as she is the light of my current life and I moved across the state to be with her and start our on life together but I can't get over my thoughts. Are they legitimate or just paranoid? It's driving me crazy and I try and bring up my thoughts with her but I feel it just comes off as needy and beating a dead horse so I don't what to do.

TL:DR: Girlfriends baby daddy has come back in the picture and I can't stop comparing myself to him, in regards to who can give her the best life