Husband is kissing family on the lips

So I am 22 weeks pregnant with mine and my husbands first baby! I just recently witnessed him kissing his aunt on the lips (just a peck) when saying hello/goodbye and it really irked me. Not only because he tried to kiss me right after that but because she has a lot of different health issues and I feel like he is exposing me and our unborn baby to a whole bunch of new germs. I am also concerned that this will be something she and his family will want to do with the baby once he’s born and I am not okay with that. Apparently kissing on the lips is a family thing for him. Granted I may just be hormonal but it is not something I’m okay with but should I be? I mentioned my concerns but my husband doesn’t think they are valid. Any thoughts, tips or advice?