You are already attractive and your sex life is taken care of. If you have some feelings now, this may be a very good thing to hook up with them. Do you really want to be with your 3some partners now? Even if you have feelings, do you want to continue to develop with your threesomes? At the beginning of the swingers app, threesome dating is always for a reason, so these questions may not always be the easiest to answer, but if you are honest with yourself, you will get the real answer.
If you are looking for something, why haven't you considered it yet? Is it because you like the relationship between you, or because you really don't look at them from a more serious perspective. It's very important to figure out where you really stand, there are many things to consider. No matter what your decision is, it will completely change things, so whether you want to be with them, you end up with a tree of love, or end up with no swingers lifestyles. Either way, you need to make a decision.
Once one of you has a feeling, you can no longer be casual. One of you always wants to get more in a three way dating, and the other always wants to know if it is a good idea to continue. When one of you catches the feeling and the other feels different, this is already a very hurtful situation, so no, things really can't stay the same. Obviously unfortunate because there is a strong comfort and physical attraction, but if this is true, then you need to make sure you make the right decision, so you won't take anyone else's situation and they will experience more damage. More than necessary.
Extending the time will definitely make it harder for them to get out of this line, so even if it's a very good physical condition, if you don't like anything, then you need to make some decisions. If you've been thinking about the same thing all the time, this is good news, and usually there won't be any meaningful things that can come out of swingers lifestyles. Obviously there are always some secrets between the three of you.
Now, if you're in one place, you want to move forward, look at the direction of things, go beyond the hooks, and realize that even if you are still intimate with your threeway partner, expectations and overall dynamics will change. This is a problem that the three of you will solve slowly, so it should be fine. Now I hope that you can give each other more outside the body.