Can you still be a good Catholic, if you fulfill your once-a-year obligation, but pray directly to God for forgiveness other times?
The requirement is that MORTAL sins be confessed once a year. So if you are doing that, then yes, technically you are fulfilling the requirement. It is also never wrong to ask God for forgiveness in your personal prayer - doesn’t take the place of confession, but it’s not wrong to do so.
As for being a “good” Catholic, that’s a tougher thing to define. First, if you have mortal sin and you wait all year for your annual confession date, you are playing with fire. If you were to die before you got to that state, your soul would be in grave danger. For that matter, your soul would be in danger while you’re alive, since you don’t know when your life might end. Is it being a “good Catholic” to risk your soul? I’m not so sure about that.
Second, although you are not required to confess venial sins, the Church recommends that you go to confession frequently and that you do confess venial sins. The most common suggestion I’ve heard is that you should go once a month. And since our Lord asks us to seek perfection (“be perfect as your heavenly Father is perfect”, or something like that), it doesn’t make sense that we would only do the bare minimum that is required if we are truly seeking to become more like Christ. So if you’re a “bare minimum” Catholic, can you also call yourself a “good Catholic?” I don’t know, but I personally don’t think it’s enough.
That said, lack of going to confession wouldn’t automatically be a deal breaker, although depending on the circumstances, it could be. If I were single, it would be a requirement that my sig. other be not just a practicing Catholic, but one that was fairly serious about his faith. However, I also would recognize that we are all on a journey in our faith, and I can imagine a scenario (in fact, this was me at one point) in which a person is serious about their faith, committed to following the Church, but hasn’t come to a complete understanding of what is required in every case, let alone WHY it’s required. Lets face it, education of Catholics has been HORRIBLE in recent decades, so lack of following the rules may not necessarily show bad intent. AND especially with guys, pride is a very difficult thing to overcome, so I can be sympathetic towards a person who is not very comfortable with finding his faults and confessing his sins. So if I were dating a non-confession-goer, I’d try to see if it’s because he was on his way to being a better Catholic, and just hadn’t gotten over that particular hurdle yet. On the other hand, if he didn’t seem to be seeking to understand and follow the Church’s authority, then I’d guess that this aspect was simply a sign of a less than serious faith, and I wouldn’t date that person.