I think it's time you and your gf find a reliable babysitter (either of your parents/siblings perhaps?) and get away for a romantic over-nighter. Bring the focus back to you two as a romantic couple rather then two parents who happen to live together.
Too many young people forget that your partner comes first (aside from the babies physical needs and well being, of course.) and when that happens, one or the other starts finding someone other then their SO pretty darn enticing. Fix this soon, Regeneration.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion